Update travis config and README with new ruby version

.travis.yml

@@ -3,7 +3,7 @@ sudo: false
 cache: bundler
 bundler_args: --without development
 rvm:
-  - "1.9.3"
+  - "2.1.5"
 
 # The test cases are roughly split according to their test times.
 # It would be better to use https://github.com/ArturT/knapsack.

README.markdown

@@ -20,7 +20,7 @@ Below are instructions for setting up a development environment for Open Food Ne
 ## Dependencies
 
 * Rails 3.2.x
-* Ruby 1.9.3
+* Ruby 2.1.5
 * PostgreSQL database
 * PhantomJS (for testing)
 * See Gemfile for a list of gems required
@@ -44,7 +44,7 @@ You can download the source with the command:
 
 For those new to Rails, the following tutorial will help get you up to speed with configuring a Rails environment: http://guides.rubyonrails.org/getting_started.html .
 
-First, check your dependencies: Ensure that you have Ruby >= 1.9.3 installed:
+First, check your dependencies: Ensure that you have Ruby 2.1.5 installed:
 
     ruby --version