.travis.yml in tracker_api-1.7.0 vs .travis.yml in tracker_api-1.7.1

@@ -1,10 +1,11 @@
+dist: trusty
 language: ruby
 rvm:
-  # - "1.9.3"
-  - "2.0.0"
-  - "2.1.0"
-  - "2.2.3"
+  - 2.1
+  - 2.2
+  - 2.3
+  - 2.4
   # - "jruby"
   #  - rbx
   #  - "1.8.7"
 # uncomment this line if your project needs to run something other than `rake`:
 # script: bundle exec rspec spec