module Apartment

def configure

configure apartment with available options 
def configure
  yield self if block_given?
  Database.init
end

def database_names

Be careful not to use `return` here so both Proc and lambda can be used without breaking 
def database_names
  if @database_names.respond_to?(:call)
    @database_names.call
  else
    @database_names
  end
end

def excluded_models

Default to none 
def excluded_models
  @excluded_models || []
end