diff --git a/.travis.yml b/.travis.yml
index 0a20de8..b3bc736 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -32,6 +32,8 @@ matrix:
       env: "RAILS_VERSION=5.2.0"
     - rvm: 2.1
       env: "RAILS_VERSION=6.0.0"
+    - rvm: 2.2
+      env: "RAILS_VERSION=5.1.0"
     - rvm: 2.2
       env: "RAILS_VERSION=6.0.0"
     - rvm: 2.3