Add a rake task that installs the gem (#121)

README.md

@@ -50,6 +50,16 @@ And then execute:
 
 If you cannot commit changes to the repo or Gemfile, consider the local Gemfile installation described in [this post](https://blog.widefix.com/personal-gemfile-for-development/).
 
+Next, generate your ActualDbSchema initializer file by running:
+
+```sh
+rake actual_db_schema:install
+```
+
+This will create a `config/initializers/actual_db_schema.rb` file with all the available configuration options so you can adjust them as needed. It will also prompt you to install the post-checkout Git hook for automatic phantom migration rollback when switching branches.
+
+For more details on the available configuration options, see the sections below.
+
 ## Usage
 
 Just run `rails db:migrate` inside the current branch. It will roll back all phantom migrations for all configured databases in your `database.yml.`
@@ -86,7 +96,7 @@ export ACTUAL_DB_SCHEMA_UI_ENABLED=true
 Add the following line to your initializer file (`config/initializers/actual_db_schema.rb`):
 
 ```ruby
-ActualDbSchema.config[:ui_enabled] = true
+config.ui_enabled = true
 ```
 
 > With this option, the UI can be disabled for all environments or be enabled in specific ones.
@@ -107,7 +117,7 @@ export ACTUAL_DB_SCHEMA_AUTO_ROLLBACK_DISABLED=true
 Add the following line to your initializer file (`config/initializers/actual_db_schema.rb`):
 
 ```ruby
-ActualDbSchema.config[:auto_rollback_disabled] = true
+config.auto_rollback_disabled = true
 ```
 
 ## Automatic Phantom Migration Rollback On Branch Switch
@@ -126,7 +136,7 @@ export ACTUAL_DB_SCHEMA_GIT_HOOKS_ENABLED=true
 Add the following line to your initializer file (`config/initializers/actual_db_schema.rb`):
 
 ```ruby
-ActualDbSchema.config[:git_hooks_enabled] = true
+config.git_hooks_enabled = true
 ```
 
 ### Installing the Post-Checkout Hook
@@ -149,13 +159,13 @@ Based on your selection, a post-checkout hook will be installed or updated in yo
 If your application leverages multiple schemas for multi-tenancy — such as those implemented by the [apartment](https://github.com/influitive/apartment) gem or similar solutions — you can configure ActualDbSchema to handle migrations across all schemas. To do so, add the following configuration to your initializer file (`config/initializers/actual_db_schema.rb`):
 
 ```ruby
-ActualDbSchema.config[:multi_tenant_schemas] = -> { # list of all active schemas }
+config.multi_tenant_schemas = -> { # list of all active schemas }
 ```
 
 ### Example:
 
 ```ruby
-ActualDbSchema.config[:multi_tenant_schemas] = -> { ["public", "tenant1", "tenant2"] }
+config.multi_tenant_schemas = -> { ["public", "tenant1", "tenant2"] }
 ```
 
 ## Development

actual_db_schema.gemspec

@@ -47,10 +47,10 @@ Gem::Specification.new do |spec|
   spec.post_install_message = <<~MSG
     Thank you for installing ActualDbSchema!
 
-    To enable automatic rollback of phantom migrations when switching branches, follow these steps:
-    1. Set `export ACTUAL_DB_SCHEMA_GIT_HOOKS_ENABLED=true` in your environment, OR
-       add `ActualDbSchema.config[:git_hooks_enabled] = true` to your initializer.
-    2. Run `rake actual_db_schema:install_git_hooks` to install the post-checkout Git hook.
+    Next steps:
+    1. Run `rake actual_db_schema:install` to generate the initializer file and install
+       the post-checkout Git hook for automatic phantom migration rollback when switching branches.
+    2. Or, if you prefer environment variables, skip this step.
 
     For more information, see the README.
 

lib/actual_db_schema.rb

@@ -4,6 +4,7 @@
 require "active_record/migration"
 require "csv"
 require_relative "actual_db_schema/git"
+require_relative "actual_db_schema/configuration"
 require_relative "actual_db_schema/store"
 require_relative "actual_db_schema/version"
 require_relative "actual_db_schema/migration"
@@ -29,12 +30,11 @@ class << self
   end
 
   self.failed = []
-  self.config = {
-    enabled: Rails.env.development?,
-    auto_rollback_disabled: ENV["ACTUAL_DB_SCHEMA_AUTO_ROLLBACK_DISABLED"].present?,
-    ui_enabled: Rails.env.development? || ENV["ACTUAL_DB_SCHEMA_UI_ENABLED"].present?,
-    git_hooks_enabled: ENV["ACTUAL_DB_SCHEMA_GIT_HOOKS_ENABLED"].present?
-  }
+  self.config = Configuration.new
+
+  def self.configure
+    yield(config)
+  end
 
   def self.migrated_folder
     migrated_folders.first

lib/actual_db_schema/configuration.rb

@@ -0,0 +1,32 @@
+# frozen_string_literal: true
+
+module ActualDbSchema
+  # Manages the configuration settings for the gem.
+  class Configuration
+    attr_accessor :enabled, :auto_rollback_disabled, :ui_enabled, :git_hooks_enabled, :multi_tenant_schemas
+
+    def initialize
+      @enabled = Rails.env.development?
+      @auto_rollback_disabled = ENV["ACTUAL_DB_SCHEMA_AUTO_ROLLBACK_DISABLED"].present?
+      @ui_enabled = Rails.env.development? || ENV["ACTUAL_DB_SCHEMA_UI_ENABLED"].present?
+      @git_hooks_enabled = ENV["ACTUAL_DB_SCHEMA_GIT_HOOKS_ENABLED"].present?
+      @multi_tenant_schemas = nil
+    end
+
+    def [](key)
+      public_send(key)
+    end
+
+    def []=(key, value)
+      public_send("#{key}=", value)
+    end
+
+    def fetch(key, default = nil)
+      if respond_to?(key)
+        public_send(key)
+      else
+        default
+      end
+    end
+  end
+end

lib/generators/actual_db_schema/templates/actual_db_schema.rb

@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+# ActualDbSchema initializer
+# Adjust the configuration as needed.
+
+ActualDbSchema.configure do |config|
+  # Enable the gem.
+  config.enabled = Rails.env.development?
+
+  # Disable automatic rollback of phantom migrations.
+  # config.auto_rollback_disabled = true
+  config.auto_rollback_disabled = ENV["ACTUAL_DB_SCHEMA_AUTO_ROLLBACK_DISABLED"].present?
+
+  # Enable the UI for managing migrations.
+  config.ui_enabled = Rails.env.development? || ENV["ACTUAL_DB_SCHEMA_UI_ENABLED"].present?
+
+  # Enable automatic phantom migration rollback on branch switch,
+  # config.git_hooks_enabled = true
+  config.git_hooks_enabled = ENV["ACTUAL_DB_SCHEMA_GIT_HOOKS_ENABLED"].present?
+
+  # If your application leverages multiple schemas for multi-tenancy, define the active schemas.
+  # config.multi_tenant_schemas = -> { ["public", "tenant1", "tenant2"] }
+end

lib/tasks/actual_db_schema.rake

@@ -1,6 +1,34 @@
 # frozen_string_literal: true
 
-namespace :actual_db_schema do
+namespace :actual_db_schema do # rubocop:disable Metrics/BlockLength
+  desc "Install ActualDbSchema initializer and post-checkout git hook."
+  task :install do
+    extend ActualDbSchema::OutputFormatter
+
+    initializer_path = Rails.root.join("config", "initializers", "actual_db_schema.rb")
+    initializer_content = File.read(
+      File.expand_path("../../lib/generators/actual_db_schema/templates/actual_db_schema.rb", __dir__)
+    )
+
+    if File.exist?(initializer_path)
+      puts colorize("[ActualDbSchema] An initializer already exists at #{initializer_path}.", :gray)
+      puts "Overwrite the existing file at #{initializer_path}? [y,n] "
+      answer = $stdin.gets.chomp.downcase
+
+      if answer.start_with?("y")
+        File.write(initializer_path, initializer_content)
+        puts colorize("[ActualDbSchema] Initializer updated successfully at #{initializer_path}", :green)
+      else
+        puts colorize("[ActualDbSchema] Skipped overwriting the initializer.", :yellow)
+      end
+    else
+      File.write(initializer_path, initializer_content)
+      puts colorize("[ActualDbSchema] Initializer created successfully at #{initializer_path}", :green)
+    end
+
+    Rake::Task["actual_db_schema:install_git_hooks"].invoke
+  end
+
   desc "Install ActualDbSchema post-checkout git hook that rolls back phantom migrations when switching branches."
   task :install_git_hooks do
     extend ActualDbSchema::OutputFormatter