def setup!
      ActiveRecord::Base.configurations[configuration_name] = db_config
      ActiveRecord::Base.establish_connection(configuration_name).connection
      self
    end
def setup!
      ActiveRecord::Base.configurations[configuration_name] = db_config
      ActiveRecord::Base.establish_connection(configuration_name).connection
      self
    end
Installs an ActiveRecord configuration based on the environment variables, and
 makes an initial connection to the database.  (This flushes out the connection
 pool if a different connection has already been established, and tests to
 make sure we can actually connect.)