Consolidate gem requirements into gemspec
Be explicit about the activesupport dependency

lib/active_record_shards/configuration_parser.rb explicitly requires
active_support/core_ext
Remove run_tests script, use wwtd instead
Stop testing against Ruby Enterprise Edition
Merge pull request #27 from zendesk/bquorning/wwtd

Remove Appraisal, use WWTD
Rails 4.1 compatibility
Pass symbols to .establish_connection

Passing a String for a configuration lookup is deprecated in Rails 4.1
HasAndBelongsToMany preloader not in Rails 4.1
Fix .establish_connection