Make access tokens belong to user not client app

app/models/o_auth_application.rb

 class OAuthApplication < ActiveRecord::Base
   belongs_to :user
 
-  validates :user_id, presence: true
   validates :client_id, presence: true, uniqueness: true
   validates :client_secret, presence: true
 
-  has_many :tokens
 end

app/models/token.rb

 class Token < ActiveRecord::Base
-  belongs_to :o_auth_application
+  belongs_to :user
 
   before_validation :setup, on: :create
 

app/models/user.rb

@@ -77,6 +77,7 @@ class User < ActiveRecord::Base
   has_many :reports
 
   has_many :o_auth_applications
+  has_many :tokens
 
   before_save :guard_unconfirmed_email,
               :save_person!

db/migrate/20150613202109_create_o_auth_applications.rb

@@ -4,6 +4,8 @@ class CreateOAuthApplications < ActiveRecord::Migration
       t.belongs_to :user, index: true
       t.string :client_id
       t.string :client_secret
+      t.string :name
+      t.string :redirect_uris
 
       t.timestamps null: false
     end

db/migrate/20150614134031_create_tokens.rb

 class CreateTokens < ActiveRecord::Migration
   def self.up
     create_table :tokens do |t|
-      t.belongs_to :o_auth_application, index: true
+      t.belongs_to :user, index: true
       t.string :token
       t.datetime :expires_at
+
       t.timestamps null: false
     end
   end

db/schema.rb

@@ -240,6 +240,8 @@ ActiveRecord::Schema.define(version: 20151003142048) do
     t.integer  "user_id",       limit: 4
     t.string   "client_id",     limit: 255
     t.string   "client_secret", limit: 255
+    t.string   "name",          limit: 255
+    t.string   "redirect_uris", limit: 255
     t.datetime "created_at",                null: false
     t.datetime "updated_at",                null: false
   end
@@ -539,14 +541,14 @@ ActiveRecord::Schema.define(version: 20151003142048) do
   add_index "tags", ["name"], name: "index_tags_on_name", unique: true, length: {"name"=>191}, using: :btree
 
   create_table "tokens", force: :cascade do |t|
-    t.integer  "o_auth_application_id", limit: 4
-    t.string   "token",                 limit: 255
+    t.integer  "user_id",    limit: 4
+    t.string   "token",      limit: 255
     t.datetime "expires_at"
-    t.datetime "created_at",                        null: false
-    t.datetime "updated_at",                        null: false
+    t.datetime "created_at",             null: false
+    t.datetime "updated_at",             null: false
   end
 
-  add_index "tokens", ["o_auth_application_id"], name: "index_tokens_on_o_auth_application_id", using: :btree
+  add_index "tokens", ["user_id"], name: "index_tokens_on_user_id", using: :btree
 
   create_table "user_preferences", force: :cascade do |t|
     t.string   "email_type", limit: 255