Build a PHP API

Hey guys, I'm a Web Developer building a website on the side using HTML, CSS and Javascript. To go forward I need someone who can help creating a simple API with PHP. Tell us more about the project : The website helps tennis teachers to schedule lessons for their students. Basically, a teacher can create a lesson (title, image, description, time, address, ...) and invite students. Students can join or decline a lesson. Students can upload photos during the lesson. They can check-in to a lesson (as Foursquare) to let their parents know where they are. Last thing, after a lesson, students can give a mark to the teacher. POST : create an user / lesson / photo. GET : return user / lesson / photo. PUT : update user / lesson / photo. DELETE : remove user / lesson / photo. API main functionnalities are : 1°/ Login with Facebook or email / Access Token. 2°/ POST user / GET user (id) / PUT user (id) / DELETE user (id) 3°/ POST lesson (id) / GET my lessons / GET lesson (id) / PUT lesson (id) / DELETE lesson (id) 4°/ POST photo / GET photos per lesson (id) / GET photo (id) / DELETE photo 5°/ ADD student per lesson (id) / GET students per lesson (id) / DELETE student per lesson. Please let me know if you have any questions and I'll try to reply as clear as possible.