Remove url options

Removing url options because It does not works at all.
Thus, there are others PR at the moment to include url(links) as well.

README.md

@@ -36,8 +36,6 @@ class PostSerializer < ActiveModel::Serializer
   attributes :title, :body
 
   has_many :comments
-
-  url :post
 end
 ```
 
@@ -48,8 +46,6 @@ class CommentSerializer < ActiveModel::Serializer
   attributes :name, :body
 
   belongs_to :post
-
-  url [:post, :comment]
 end
 ```
 
@@ -239,8 +235,6 @@ class PostSerializer < ActiveModel::Serializer
 
   has_many :comments
   has_one :author
-
-  url :post
 end
 ```
 
@@ -251,8 +245,6 @@ class CommentSerializer < ActiveModel::Serializer
   attributes :name, :body
 
   belongs_to :post_id
-
-  url [:post, :comment]
 end
 ```
 
@@ -274,8 +266,6 @@ And you can change the JSON key that the serializer should use for a particular
   has_many :comments, key: :reviews
 ```
 
-The `url` declaration describes which named routes to use while generating URLs
-for your JSON. Not every adapter will require URLs.
 ## Pagination
 
 Pagination links will be included in your response automatically as long as the resource is paginated using [Kaminari](https://github.com/amatsuda/kaminari) or [WillPaginate](https://github.com/mislav/will_paginate) and if you are using a ```JSON-API``` adapter.
@@ -307,8 +297,6 @@ class PostSerializer < ActiveModel::Serializer
   attributes :title, :body
 
   has_many :comments
-
-  url :post
 end
 ```
 
@@ -332,8 +320,6 @@ class PostSerializer < ActiveModel::Serializer
   attributes :title, :body
 
   has_many :comments
-
-  url :post
 end
 ```
 

lib/active_model/serializer.rb

@@ -31,7 +31,6 @@ class Serializer
     class << self
       attr_accessor :_attributes
       attr_accessor :_attributes_keys
-      attr_accessor :_urls
       attr_accessor :_cache
       attr_accessor :_fragmented
       attr_accessor :_cache_key
@@ -44,7 +43,6 @@ class << self
     def self.inherited(base)
       base._attributes = self._attributes.try(:dup) || []
       base._attributes_keys = self._attributes_keys.try(:dup) || {}
-      base._urls = []
       base._cache_digest = digest_caller_file(caller.first)
       super
     end
@@ -86,14 +84,6 @@ def self.cache(options = {})
       @_cache_options = (options.empty?) ? nil : options
     end
 
-    def self.url(attr)
-      @_urls.push attr
-    end
-
-    def self.urls(*attrs)
-      @_urls.concat attrs
-    end
-
     def self.serializer_for(resource, options = {})
       if resource.respond_to?(:serializer_class)
         resource.serializer_class

test/fixtures/active_record.rb

@@ -40,7 +40,6 @@ class PostSerializer < ActiveModel::Serializer
 
     has_many :comments
     belongs_to :author
-    url :comments
   end
 
   class CommentSerializer < ActiveModel::Serializer

test/fixtures/poro.rb

@@ -59,17 +59,13 @@ class Profile < Model
 class ProfileSerializer < ActiveModel::Serializer
   attributes :name, :description
 
-  urls :posts, :comments
-
   def arguments_passed_in?
     options[:my_options] == :accessible
   end
 end
 
 class ProfilePreviewSerializer < ActiveModel::Serializer
   attributes :name
-
-  urls :posts, :comments
 end
 
 Post     = Class.new(Model)
@@ -100,7 +96,6 @@ module Spam; end
   has_many :comments
   belongs_to :blog
   belongs_to :author
-  url :comments
 
   def blog
     Blog.new(id: 999, name: 'Custom blog')