def mongodb_connection(options={}, &block)
      return @mongodb_conncetion if @mongodb_connection and !block_given?
      options.stringify_keys!
      options['adapter'] ||= 'mongodb'
      @mongodb_connection = no_sql_connection(options, &block)
    end
def mongodb_connection(options={}, &block)
      return @mongodb_conncetion if @mongodb_connection and !block_given?
      options.stringify_keys!
      options['adapter'] ||= 'mongodb'
      @mongodb_connection = no_sql_connection(options, &block)
    end
self
 Returns a no_sql_connection which is bound to a mongodb adapter
 or builds a new no_sql_connection if block is given