Fix CI issue

Author: MUTOgen

specs_e2e/rails_4_2/Gemfile

@@ -3,6 +3,7 @@ source 'https://rubygems.org'
 # Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
 gem 'rails', '~> 4.2.10'
 gem 'sprockets', '~> 3.7.2'
+gem 'bigdecimal', '1.3.5'
 
 group :development, :test do
   gem 'vcr'