add an explicit ruby version

Jon Mountjoy · Jon Mountjoy · commit 0c4f3886ee4e · 2014-07-07T13:12:11.000+01:00
diff --git a/Gemfile b/Gemfile
@@ -1,5 +1,5 @@
 source 'https://rubygems.org'
-
+ruby '2.1.1'
 
 # Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
 gem 'rails', '4.1.4'
