not sure forcing compatibility with old ruby version is necessary, removing for now

GitBytes · GitBytes · commit d1be5e3387d7 · 2016-09-28T15:28:45.000-07:00
diff --git a/.travis.yml b/.travis.yml
@@ -1,6 +1,5 @@
 language: ruby
 rvm:
-  - 2.1.9
   - 2.2.5
   - 2.3.1
 

-Original file line number
+Diff line change
@@ @@ -1,6 +1,5 @@ @@
 language: ruby
 rvm:
 -  - 2.1.9
   - 2.2.5
   - 2.3.1