Lock Rails version to 4.2 instead of master.

Author: bigxiang

.travis.yml

@@ -15,24 +15,24 @@ env:
   global:
     - SQ_CONFIG_FILE=$TRAVIS_BUILD_DIR/spec/config.travis.yml
   matrix:
-    - RAILS=master AREL=master ADAPTER=sqlite3
+    - RAILS=4-2-stable AREL=6-0-stable ADAPTER=sqlite3
     - RAILS=4-1-stable AREL=5-0-stable ADAPTER=sqlite3
     - RAILS=4-0-stable AREL=4-0-stable ADAPTER=sqlite3
     - RAILS=3-2-stable AREL=3-0-stable ADAPTER=sqlite3
     - RAILS=3-1-stable AREL=2-2-stable ADAPTER=sqlite3
     - RAILS=3-0-stable AREL=2-0-stable ADAPTER=sqlite3
-    - RAILS=master AREL=master ADAPTER=mysql
+    - RAILS=4-2-stable AREL=6-0-stable ADAPTER=mysql
     - RAILS=4-1-stable AREL=5-0-stable ADAPTER=mysql
     - RAILS=4-0-stable AREL=4-0-stable ADAPTER=mysql
     - RAILS=3-2-stable AREL=3-0-stable ADAPTER=mysql
     - RAILS=3-1-stable AREL=2-2-stable ADAPTER=mysql
     - RAILS=3-0-stable AREL=2-0-stable ADAPTER=mysql
-    - RAILS=master AREL=master ADAPTER=mysql2
+    - RAILS=4-2-stable AREL=6-0-stable ADAPTER=mysql2
     - RAILS=4-1-stable AREL=5-0-stable ADAPTER=mysql2
     - RAILS=4-0-stable AREL=4-0-stable ADAPTER=mysql2
     - RAILS=3-2-stable AREL=3-0-stable ADAPTER=mysql2
     - RAILS=3-1-stable AREL=2-2-stable ADAPTER=mysql2
-    - RAILS=master AREL=master ADAPTER=postgresql
+    - RAILS=4-2-stable AREL=6-0-stable ADAPTER=postgresql
     - RAILS=4-1-stable AREL=5-0-stable ADAPTER=postgresql
     - RAILS=4-0-stable AREL=4-0-stable ADAPTER=postgresql
     - RAILS=3-2-stable AREL=3-0-stable ADAPTER=postgresql

Gemfile

@@ -3,12 +3,8 @@ gemspec
 
 gem 'rake'
 
-rails = ENV['RAILS'] || 'master'
-arel = ENV['AREL'] || 'master'
-
-if rails == 'master'
-  gem 'i18n', github: 'svenfuchs/i18n', branch: 'master'
-end
+rails = ENV['RAILS'] || '4-2-stable'
+arel = ENV['AREL'] || '6-0-stable'
 
 arel_opts = case arel
 when /\// # A path