def add_configuration(config_hash)
      config_hash.each do |key, val|
        instance_eval { instance_variable_set("@#{key}",val) }
        self.class.instance_eval { attr_accessor key }
      end
    end
def add_configuration(config_hash)
      config_hash.each do |key, val|
        instance_eval { instance_variable_set("@#{key}",val) }
        self.class.instance_eval { attr_accessor key }
      end
    end
Extend configuration variables

 @param config_hash [Hash]

 @example
   IronHide.configuration.add_configuration(couchdb_server: 'http://127.0.0.1:5984')
   IronHide.configuration.couchdb_server)
   #=> 'http://127.0.0.1:5984'

   IronHide.configuration.couchdb_server = 'other'
   #=> 'other'