PHP: implement oAuth authentication in Slim REST API

General information for the website: oAuth for a RESTful API in PHP (Slim)
Description of requirements/features: We are looking for a PHP Freelance with experience with Slim Framework, to implement an oAuth authentication system in a PHP REST API.

We have an already working API done with Slim Framework, and we are in need of an oAuth middleware to provide security to our API, the job will be to implement the oAuth with JWT (JSON Web Token) to be used from an angular app.

It needs to recieve the user/pass the first time that a user tries to connect and provide a token that will be used in all forthcoming connections to the API.

Let us know your time and price for this task, as well as your experience with PHP and Slim; and of course ask me any questions if something is not clear in this request.

Thanks.
Extra services needed: Security
Extra notes: