Christian DONGMO

[backend] add query to fetch documents

1

### Proposed changes * * ### Related issues * * ### Checklist - [x ] I consider the submitted work as finished - [ ] I tested the code for...

[Frontend][Backend] duplicate an exercise

6

### Proposed changes * * ### Related issues * * ### Checklist - [x] I consider the submitted work as finished - [x] I tested the code for its functionality...