API and Database Development

I am looking for a freelancer to help me with my project. The skills required are back-end API and Database Development. A front-end designer has already been hired and the hire in this case will need to converse with this front-end developer integrating the front-end with the API's. A detailed draft spec of the back-end database has been created in relational format. This can be passed to interested candidates on demand. This is as a guide and the designer has free rein with regards to their choice of db platform (use of NoSQL platforms is also ok provided the application requirements are met). Choice of API Programming language is also up to the developer. The website itself will be competition based primarily targeting amateur sports clubs looking to raise funds. Players will pay a feee to enter a compeition with 90% of the fees going to the club. 10% will go to the site owners. However, it can also be used to setup private competition leagues (not a club fundraiser) where a group of friends can raise a pot of money and the winner takes the prize. The competition will consist of a number of prediction questions (15-20) that each player must answer. Each potential right answer will offer a different amount of points. Once the outcome of all these predictions is known and updated within the web application, the player with the most correct number of prediction and points will win the game. More details can be passed to interested developers. This site will need secure login and payment processing facilities as well as the application functionality. An admin interface for site owners will also be required as well as the player interface. All details to be provided.