diff --git a/.rubocop.yml b/.rubocop.yml
new file mode 100644
index 0000000..4f3c2c0
--- /dev/null
+++ b/.rubocop.yml
@@ -0,0 +1,8 @@
+Metrics/LineLength:
+  Max: 116
+
+Style/Documentation:
+  Enabled: false
+
+Style/ModuleFunction:
+  EnforcedStyle: 'extend_self'
diff --git a/Gemfile b/Gemfile
index 26d6125..35292ff 100644
--- a/Gemfile
+++ b/Gemfile
@@ -2,12 +2,3 @@ source 'https://rubygems.org'
 
 # Specify your gem's dependencies in divisio.gemspec
 gemspec
-
-group :development, :test do
-  gem 'pry-plus'
-  gem 'mongoid'
-end
-
-group :test do
-  gem 'rspec'
-end
diff --git a/README.md b/README.md
index 387dae5..ae7c794 100644
--- a/README.md
+++ b/README.md
@@ -43,7 +43,7 @@ Divisio.new.split(experiment_name, variants, identity) # ==>> 1
 
 ### Mongoid adaper
 
-_Requires mongoid v4.0.0 or greater_
+_Requires mongoid v5.0.0 or greater_
 
 This adapter will persist the experiment name, identifier, and variant information in a MongoDb collection called `experiments`. Note: The variant returned will be cast to a string.
 
diff --git a/divisio.gemspec b/divisio.gemspec
index 52bc1eb..34f945b 100644
--- a/divisio.gemspec
+++ b/divisio.gemspec
@@ -8,8 +8,8 @@ Gem::Specification.new do |spec|
   spec.version       = Divisio::VERSION
   spec.authors       = ['Dragos Miron']
   spec.email         = ['tech@simplybusiness.co.uk']
-  spec.summary       = %q{Provides a splitting framework similar to AB testing}
-  spec.description   = %q{Provides a splitting framework similar to AB testing}
+  spec.summary       = 'Provides a splitting framework similar to AB testing'
+  spec.description   = 'Provides a splitting framework similar to AB testing'
   spec.homepage      = 'http://www.simplybusiness.co.uk'
   spec.license       = 'MIT'
 
@@ -17,4 +17,8 @@ Gem::Specification.new do |spec|
   spec.executables   = spec.files.grep(%r{^bin/}) { |f| File.basename(f) }
   spec.test_files    = spec.files.grep(%r{^(test|spec|features)/})
   spec.require_paths = ['lib']
+
+  spec.add_development_dependency 'mongoid', '~> 6.0'
+  spec.add_development_dependency 'rspec', '~> 3.5'
+  spec.add_development_dependency 'rubocop', '~> 0.46'
 end
diff --git a/lib/divisio.rb b/lib/divisio.rb
index 9679976..8b02b92 100644
--- a/lib/divisio.rb
+++ b/lib/divisio.rb
@@ -4,7 +4,6 @@
 require 'divisio/mongoid_adapter' if defined? Mongoid
 
 class Divisio
-
   @default_adapter = Divisio::NoPersistenceAdapter
   class << self
     attr_accessor :default_adapter
diff --git a/lib/divisio/base_adapter.rb b/lib/divisio/base_adapter.rb
index b44fcdd..2169161 100644
--- a/lib/divisio/base_adapter.rb
+++ b/lib/divisio/base_adapter.rb
@@ -3,10 +3,10 @@ module BaseAdapter
     extend self
 
     def split(experiment_name, variants, identity)
-      ModuloAlgorithm.new(experiment_name.to_s+identity.to_s, variants).calc
+      ModuloAlgorithm.new(experiment_name.to_s + identity.to_s, variants).calc
     end
 
-    def delete_experiment_for_identity(identity, experiment_name)
+    def delete_experiment_for_identity(_identity, _experiment_name)
       raise NotImplementedError
     end
   end
diff --git a/lib/divisio/modulo_algorithm.rb b/lib/divisio/modulo_algorithm.rb
index 3d95cf5..417b508 100644
--- a/lib/divisio/modulo_algorithm.rb
+++ b/lib/divisio/modulo_algorithm.rb
@@ -1,6 +1,5 @@
 class Divisio
   class ModuloAlgorithm
-
     attr_reader :key, :variants
     private :key, :variants
 
diff --git a/lib/divisio/mongoid_adapter.rb b/lib/divisio/mongoid_adapter.rb
index 999db4b..0c5b954 100644
--- a/lib/divisio/mongoid_adapter.rb
+++ b/lib/divisio/mongoid_adapter.rb
@@ -23,7 +23,7 @@ def delete_experiment_for_identity(identity, experiment_name)
       experiment_object = Experiment.where(identifier: identity, name: experiment_name).first
 
       return experiment_object.destroy if experiment_object
-      return false
+      false
     end
   end
 end
diff --git a/lib/divisio/mongoid_adapter/experiment.rb b/lib/divisio/mongoid_adapter/experiment.rb
index b9fccee..0f23537 100644
--- a/lib/divisio/mongoid_adapter/experiment.rb
+++ b/lib/divisio/mongoid_adapter/experiment.rb
@@ -1,7 +1,6 @@
 class Divisio
   module MongoidAdapter
     class Experiment
-
       include Mongoid::Document
       include Mongoid::Timestamps
 
@@ -12,8 +11,7 @@ class Experiment
       field :identifier, type: String
       field :variant, type: String
 
-      index({ name: 1, identifier: 1}, { unique: true})
-
+      index({ name: 1, identifier: 1 }, unique: true)
     end
   end
 end
diff --git a/lib/divisio/version.rb b/lib/divisio/version.rb
index 0742630..134ff08 100644
--- a/lib/divisio/version.rb
+++ b/lib/divisio/version.rb
@@ -1,3 +1,3 @@
 class Divisio
-  VERSION = '0.1.0'
+  VERSION = '0.2.0'.freeze
 end
diff --git a/mongoid.yml b/mongoid.yml
index d17aca0..07f6fa3 100644
--- a/mongoid.yml
+++ b/mongoid.yml
@@ -1,8 +1,6 @@
 test:
-  sessions:
+  clients:
     default:
       database: divisio_test
       hosts:
         - localhost:27017
-      options:
-        <%= "safe: true" if Mongoid::VERSION =~ /^3/%>
diff --git a/spec/divisio/base_adapter_spec.rb b/spec/divisio/base_adapter_spec.rb
index 36152e5..602b8c3 100644
--- a/spec/divisio/base_adapter_spec.rb
+++ b/spec/divisio/base_adapter_spec.rb
@@ -1,4 +1,3 @@
 describe Divisio::BaseAdapter do
-
   it_behaves_like 'a base adapter'
 end
diff --git a/spec/divisio/modulo_algorithm_spec.rb b/spec/divisio/modulo_algorithm_spec.rb
index ff07cb8..82b8b2d 100644
--- a/spec/divisio/modulo_algorithm_spec.rb
+++ b/spec/divisio/modulo_algorithm_spec.rb
@@ -1,6 +1,6 @@
 describe Divisio::ModuloAlgorithm do
   describe '#calc' do
-    let(:variants) {  }
+    let(:variants) {}
 
     context 'when there is one variant provided' do
       let(:variants) { 1 }
@@ -11,9 +11,9 @@
     end
 
     context 'when there are multiple variants provided' do
-      let(:variants) { ['1', '2', '3'] }
+      let(:variants) { %w(1 2 3) }
 
-      { blah8: '1', blah4: '2', blah0: '3'}.each_pair do |key, expected_variant|
+      { blah8: '1', blah4: '2', blah0: '3' }.each_pair do |key, expected_variant|
         it "returns the variant based on the key provided: #{key}" do
           expect(Divisio::ModuloAlgorithm.new(key, variants).calc).to eq(expected_variant)
         end
@@ -23,7 +23,7 @@
     context 'when there are multiple weighted variants provided' do
       let(:variants) { { a: 1, b: 2, c: 3 } }
 
-      { blah8: :a, blah4: :b, blah0: :c}.each_pair do |key, expected_variant|
+      { blah8: :a, blah4: :b, blah0: :c }.each_pair do |key, expected_variant|
         it "returns the variant based on the key provided and weight: #{key}" do
           expect(Divisio::ModuloAlgorithm.new(key, variants).calc).to eq(expected_variant)
         end
diff --git a/spec/divisio/mongoid_adapter/experiment_spec.rb b/spec/divisio/mongoid_adapter/experiment_spec.rb
index e793682..4db07e4 100644
--- a/spec/divisio/mongoid_adapter/experiment_spec.rb
+++ b/spec/divisio/mongoid_adapter/experiment_spec.rb
@@ -1,36 +1,34 @@
 describe Divisio::MongoidAdapter::Experiment do
   describe '#save' do
-
-    let(:required_fields) { {:name => 'experiment', :identifier => 'hash', :variant => '2'} }
+    let(:required_fields) { { name: 'experiment', identifier: 'hash', variant: '2' } }
     subject { Divisio::MongoidAdapter::Experiment.new }
 
     context 'all fields are present' do
       it 'gets saved to the database' do
         subject.attributes = required_fields
 
-        expect{ subject.save }.to change{ described_class.count }.from(0).to(1)
+        expect { subject.save }.to change { described_class.count }.from(0).to(1)
       end
     end
 
     context 'missing fields' do
       it 'does not get saved if identifier is missing' do
-        subject.attributes = required_fields.tap{ |h| h.delete(:identifier) }
+        subject.attributes = required_fields.tap { |h| h.delete(:identifier) }
         expect(subject.save).to be_falsey
       end
 
       it 'does not get saved if name is missing' do
-        subject.attributes = required_fields.tap{ |h| h.delete(:name) }
+        subject.attributes = required_fields.tap { |h| h.delete(:name) }
         expect(subject.save).to be_falsey
       end
 
       it 'does not get saved if variant is missing' do
-        subject.attributes = required_fields.tap{ |h| h.delete(:variant) }
+        subject.attributes = required_fields.tap { |h| h.delete(:variant) }
         expect(subject.save).to be_falsey
       end
     end
 
     context 'uniqueness' do
-
       it 'does not save second object with the same name and identifier' do
         subject.attributes = required_fields
         subject.save
@@ -39,16 +37,16 @@
         required_fields[:variant] = '3'
         new_object = described_class.new(required_fields)
 
-        expect{ new_object.save }.to_not change(described_class, :count)
+        expect { new_object.save }.to_not change(described_class, :count)
       end
 
       it 'does not save second object in case of race condition because of mongo index' do
         described_class.create_indexes
-        Mongoid.default_session[:divisio_mongoid_adapter_experiments].insert(required_fields)
+        Mongoid::Clients.default[:divisio_mongoid_adapter_experiments].insert_one(required_fields)
         expect(described_class.count).to eq(1)
 
         collection = described_class.collection
-        expect{collection.insert(required_fields)}.to raise_exception(Moped::Errors::OperationFailure)
+        expect { collection.insert_one(required_fields) }.to raise_exception(Mongo::Error::OperationFailure)
       end
     end
   end
diff --git a/spec/divisio/mongoid_adapter_spec.rb b/spec/divisio/mongoid_adapter_spec.rb
index 148240e..be7d0ac 100644
--- a/spec/divisio/mongoid_adapter_spec.rb
+++ b/spec/divisio/mongoid_adapter_spec.rb
@@ -4,12 +4,11 @@
   let(:identity)   { 'identity' }
 
   describe '::split' do
-    subject{ described_class.split(experiment, variants, identity) }
+    subject { described_class.split(experiment, variants, identity) }
 
     it_behaves_like 'a base adapter'
 
     context 'new record' do
-
       it 'saves the experiment to the database' do
         expect_any_instance_of(Divisio::MongoidAdapter::Experiment).to receive(:save)
         subject
@@ -21,7 +20,6 @@
     end
 
     context 'old record' do
-
       before do
         Divisio::MongoidAdapter::Experiment.create(name: experiment, identifier: identity, variant: 'random')
       end
@@ -38,7 +36,7 @@
   end
 
   describe '::delete_experiment_for_identity' do
-    subject{ described_class.delete_experiment_for_identity(identity, experiment) }
+    subject { described_class.delete_experiment_for_identity(identity, experiment) }
 
     context 'record exists in the database' do
       before do
@@ -46,7 +44,7 @@
       end
 
       it 'deletes the record' do
-        expect{subject}.to change { Divisio::MongoidAdapter::Experiment.count }.from(1).to(0)
+        expect { subject }.to change { Divisio::MongoidAdapter::Experiment.count }.from(1).to(0)
       end
 
       it 'returns true' do
diff --git a/spec/divisio/no_persistence_adapter_spec.rb b/spec/divisio/no_persistence_adapter_spec.rb
index 66f1d0f..1c45aea 100644
--- a/spec/divisio/no_persistence_adapter_spec.rb
+++ b/spec/divisio/no_persistence_adapter_spec.rb
@@ -1,4 +1,3 @@
 describe Divisio::NoPersistenceAdapter do
-
   it_behaves_like 'a base adapter'
 end
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 1b92253..66ec413 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -1,6 +1,6 @@
 ENV['RACK_ENV'] = 'test'
 
-Dir['./spec/support/**/*.rb'].sort.each { |f| require f}
+Dir['./spec/support/**/*.rb'].sort.each { |f| require f }
 
 require 'mongoid'
 require 'divisio'
@@ -9,6 +9,6 @@
 
 RSpec.configure do |config|
   config.before(:each) do
-    Mongoid::Sessions.default.collections.each(&:drop)
+    Mongoid.purge!
   end
 end
diff --git a/spec/support/shared_examples_for_base_adapter.rb b/spec/support/shared_examples_for_base_adapter.rb
index 79d9540..58e539b 100644
--- a/spec/support/shared_examples_for_base_adapter.rb
+++ b/spec/support/shared_examples_for_base_adapter.rb
@@ -1,10 +1,9 @@
 shared_examples_for 'a base adapter' do
-
   describe '::split' do
     let(:experiment) { 'experiment' }
-    let(:variants)   { ['1', '2', '3'] }
+    let(:variants)   { %w(1 2 3) }
     let(:identity)   { 'identity' }
-    subject{ described_class.split(experiment, variants, identity) }
+    subject { described_class.split(experiment, variants, identity) }
 
     it 'returns a variant for the given experiment and identity' do
       expect(subject).to eq('3')