recommender prototype

Hi  @pmitros  @jarv  @singingwolfboy ,

We have built a module where students can recommend useful resources for problems and share resources with their fellows. We are going to test our module in one place of one course, and asking for code checking. We want to make sure there is no security issue and our code won't crash the server. Since it is an R&D prototype, and we are not launching it as a product, problems such as poor coding style or user experience are OK. We would appreciate your help.