Replace logo, fix #57 - delete/unreblog/unfavourite API, fix #45 - app

registration API

db/migrate/20160926213048_remove_owner_from_application.rb

@@ -0,0 +1,7 @@
+class RemoveOwnerFromApplication < ActiveRecord::Migration[5.0]
+  def change
+    remove_index :oauth_applications, [:owner_id, :owner_type]
+    remove_column :oauth_applications, :owner_id, :integer, null: true
+    remove_column :oauth_applications, :owner_type, :string, null: true
+  end
+end