Create a PHP frontend allowing users to save and run code snippets

We provide educational software that teaches students how to write PHP code snippets. The problem is that they need to have their own web hosting and database to test their code, but most of them don't have this. We want to provide a simple web frontend where they can enter their code snippets, which then get saved (via FTP) to a web server. They will then be shown the URL for their code, and they can test it out. Obviously each user needs to be sandboxed so their code can't interfere with other users. We have lots of ideas for extending this functionality, but for stage 1 we just want a simple interface with limited features. We realise that the scope is hard to define which is why we will pay per hour. We will evaluate the progress along the way to see how far we take the project.