.travis.yml in bitzer_store-1.0.2 vs .travis.yml in bitzer_store-1.0.3

@@ -3,18 +3,16 @@
   - gem install bundler
 before_script:
   - bundle update
 cache: bundler
 rvm:
-  - 2.1.10
-  - 2.2.6
-  - 2.3.3
-  - 2.4.0
+  - 2.2.9
+  - 2.3.6
+  - 2.4.3
+  - 2.5.0
 gemfile:
   - gemfiles/rails42.gemfile
   - gemfiles/rails50.gemfile
+  - gemfiles/rails51.gemfile
 matrix:
-  exclude:
-    - rvm: 2.1.10
-      gemfile: gemfiles/rails50.gemfile
   fast_finish: true
 bundler_args: --jobs 3 --retry 3