message: Document 'cratesfyi database blacklist list' command
diff: @@ -167,8 +167,10 @@ docker exec -it <the container name goes here> psql -U cratesfyi
  The database contains a blacklist of crates that should not be built.
  ```sh
  +# List the crates on the blacklist
  +docker-compose run web database blacklist list
  +
  # Adds <CRATE_NAME> to the blacklist
  -# Crates on the blacklist will not be built
  docker-compose run web database blacklist add <CRATE_NAME>
  # Removes <CRATE_NAME> from the blacklist
  