Revert "Merge pull request #196 from edx/platform/upgrade-to-ruby23"

This reverts commit 22178086, reversing
changes made to 14ed8a85.

.travis.yml

@@ -3,7 +3,7 @@ sudo: false
 language: ruby
 
 rvm:
-  - "2.3.0"
+  - "1.9.3"
 
 cache: bundler
 

Gemfile

 source 'https://rubygems.org'
-ruby "2.3.0"
+ruby "1.9.3"
 
 gem 'pry'
 gem 'pry-nav'