Added add() method to RecipesController REST example

Copy / Pasting the example worked fine except for the missing POST /recipes.json example: add() method was missing.
Merge pull request #1824 from stefanvangastel/patch-1

Added add() method to RecipesController REST example
[zh_CN] fix error of duplicate source code indications
Merge pull request #1826 from blackpuppy/zh

[zh_CN] fix error of duplicate source code indications