update travis script

Author: bolandrm

.travis.yml

@@ -5,17 +5,16 @@ bundler_args: "--binstubs --standalone --without documentation --path ../bundle"
 script: "bundle exec rake test"
 
 gemfile:
-  - gemfiles/sprockets_2_12.gemfile
+  - gemfiles/sprockets-rails_3_0.gemfile
+  - gemfiles/sprockets-rails_2_3.gemfile
   - gemfiles/sprockets_3_0.gemfile
   - gemfiles/sprockets_4_0.gemfile
-  - gemfiles/sprockets-rails_3_0.gemfile
   - gemfiles/rails_4_2.gemfile
-  - gemfiles/rails_4_1.gemfile
-  - gemfiles/rails_4_0.gemfile
+  - gemfiles/rails_5_2.gemfile
 
 rvm:
-  - 2.2.2
-  - 2.3.0
+  - 2.4.4
+  - 2.5.1
 
 notifications:
   email: false