### What problem does this PR solve?
Adds the API method of updating documents.
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
### What problem does this PR solve?
Adds the api of listing documentation.
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
### What problem does this PR solve?
Adds the functionality of deleting documentation
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
### What problem does this PR solve?
API: Adds the feature of uploading document.
### Type of change
- [x] New Feature (non-breaking change which adds functionality)