Rails 4 class method 使用 alias_attribute, alias_method_chain, delegate, mattr_accessor

很需要了解並且熟悉這些method 的用法

http://api.rubyonrails.org/classes/Module.html#method-i-mattr_accessor

    Methods

A

• alias_attribute, 
• alias_method_chain, 
• anonymous?, 
• attr_internal, 
• attr_internal_accessor, 
• attr_internal_reader, 
• attr_internal_writer

C

• cattr_accessor, 
• cattr_reader, 
• cattr_writer

D

• delegate, 
• deprecate

F

• foo

M

• mattr_accessor, 
• mattr_reader, 
• mattr_writer

P

• parent, 
• parent_name, 
• parents

Q

• qualified_const_defined?, 
• qualified_const_get, 
• qualified_const_set

R

• redefine_method, 
• remove_possible_method