Bump ruby version to latest 2.2.x (2.2.27)

.ruby-version

@@ -1 +1 @@
-2.1.8
+2.2.7

.travis.yml

@@ -1,7 +1,7 @@
 language: ruby
 script: 'script/travis-ci'
 rvm:
-  - 2.1.8
+  - 2.2.7
 notifications:
   email: false
 

Gemfile

@@ -1,5 +1,5 @@
 source 'https://rubygems.org'
-ruby "2.1.8"
+ruby "2.2.7"
 
 gem 'rails', '4.2.6'
 gem 'rails_12factor', group: :production

Gemfile.lock

@@ -304,7 +304,7 @@ DEPENDENCIES
   yajl-ruby
 
 RUBY VERSION
-   ruby 2.1.8p440
+   ruby 2.2.7p470
 
 BUNDLED WITH
-   1.14.6
+   1.15.4

README.md

@@ -10,7 +10,7 @@ This app is written in Ruby on Rails and deployed on Heroku.
 
 You'll need a Ruby environment to run Rails.  First do:
 
-    $ rvm use 2.1.8
+    $ rvm use 2.2.7
     $ bundle install
 
 Then you need to create the database structure: