Which License is best suited for my open source project. I am developing a web app (a template like) that has potential use in real life applications but also learning outcomes. I would like people to contribute and use if they want to, so I am between using MIT or GNU GPLv3. I know GNU is a lot more restrictive and could potentially scare people away from contributing but also I would like people to contribute and keep it open source. I would not mind people using my code, but I would want something in return, even a bug reporting would be sufficient.
Based on this, and your experience or knowledge, which license would be more suitable.
Edit #1: I want to choose a licensee that's going to make users more likely to contribute, not one that forces them to.
"but I would want something in return"
Clarification: I don't mean that I would require to do that, but would be desirable and not essential.