.travis.yml in maily-0.6.3 vs .travis.yml in maily-0.7.0

@@ -3,21 +3,15 @@
 cache: bundler
 
 sudo: false
 
 rvm:
-  - 2.4.1
-  - 2.3.4
-  - 2.2.7
-  - 2.1
+  - 2.5.1
+  - 2.4.4
+  - 2.3.6
+  - 2.2.9
 
 gemfile:
+  - gemfiles/rails_5.2.gemfile
   - gemfiles/rails_5.1.gemfile
   - gemfiles/rails_5.0.gemfile
   - gemfiles/rails_4.2.gemfile
-
-matrix:
-  exclude:
-    - rvm: 2.1
-      gemfile: gemfiles/rails_5.0.gemfile
-    - rvm: 2.1
-      gemfile: gemfiles/rails_5.1.gemfile