Added pkg_resources to troubleshooting

TROUBLESHOOTING.md

@@ -15,10 +15,20 @@ You can follow [Docker's official guide](https://docs.docker.com/compose/install
 
 ## Problems with the database
 
-## Locked database
+### Locked database
 
 You can't have more than one instance of Vectory running at the same time. If you try to start Vectory while it's already running, you'll get an error message like this:
 ```bash
 sqlite3.OperationalError: database is locked
 ```
-Just stop the running instance of Vectory and try again.
+Just stop the running instance of Vectory and try again.
+
+## Import errors
+
+### No module `pkg_resources`
+
+The Python module `setuptools` has errors if installed with `pip` or `poetry`. You can fix this with:
+
+```bash
+wget https://bootstrap.pypa.io/ez_setup.py -O - | python
+```