def update_attributes(atts)
      atts.delete('_type')
      atts.each { |att, val| send(:"#{att}=", val) }
    end
def update_attributes(atts)
      atts.delete('_type')
      atts.each { |att, val| send(:"#{att}=", val) }
    end
Initialize a model using a dictionary of attributes.

 Example:

   u = User.new(:name => "John")

 Write the dictionary of key-value pairs to the model.