Pass the symbol :sqlite instead of the string “sqlite” to establish_connection due to:

DEPRECATION WARNING: Passing a string to ActiveRecord::Base.establish_connection for a configuration lookup is deprecated, please pass a symbol (:sqlite3) instead.
Remove the old gemfiles in preparation for appraisals.
Start using appraisal for testing and also test Rails 4.1.
Merge branch 'master' of github.com:watu/random_unique_id