Support Rails 6.0.0

Author: yahonda

gemfiles/6.0.gemfile

@@ -4,7 +4,7 @@ source "https://rubygems.org"
 
 gem "rake"
 gem "appraisal"
-gem "activesupport", "~> 6.0.0.rc2"
+gem "activesupport", "~> 6.0.0"
 gem "addressable", "~> 2.2"
 gem "codeclimate-test-reporter", :group => :test, :require => nil