Merge pull request #1188 from lgebhardt/update_travis_matrix

Update ruby and rails versions for travis tests

Author: lgebhardt

.travis.yml

@@ -1,22 +1,15 @@
 language: ruby
 sudo: false
 env:
-  - "RAILS_VERSION=4.2.8"
-  - "RAILS_VERSION=5.0.2"
-  - "RAILS_VERSION=5.1.0"
+  - "RAILS_VERSION=4.2.10"
+  - "RAILS_VERSION=5.0.7"
+  - "RAILS_VERSION=5.1.6"
+  - "RAILS_VERSION=5.2.1"
   - "RAILS_VERSION=master"
 rvm:
-  - 2.1.10
-  - 2.2.7
-  - 2.3.4
-  - 2.4.1
+  - 2.3.7
+  - 2.4.4
+  - 2.5.1
 matrix:
-  exclude:
-    - rvm: 2.1.10
-      env: "RAILS_VERSION=5.0.2"
-    - rvm: 2.1.10
-      env: "RAILS_VERSION=5.1.0"
-    - rvm: 2.1.10
-      env: "RAILS_VERSION=master"
   allow_failures:
     - env: "RAILS_VERSION=master"