Fix typo in docs

Author: sodic

web/docs/data-model/backends.md

@@ -50,6 +50,7 @@ app MyApp {
 ```bash
 rm -r migrations/
 wasp clean
+```
 
 3. Ensure your new database is running (check the [section on connecing to a database](#connecting-to-a-database) to see how). Leave it running, since we need it for the next step.
 4. In a different terminal, run `wasp db migrate-dev` to apply the changes and create a new initial migration.