Fix connections.py: allow to connect to Redis using a Unix socket URL without specifying the database number

Author: drygdryg

arq/connections.py

@@ -55,8 +55,10 @@ def from_dsn(cls, dsn: str) -> 'RedisSettings':
         if query_db:
             # e.g. redis://localhost:6379?db=1
             database = int(query_db[0])
-        else:
+        elif conf.scheme != 'unix':
             database = int(conf.path.lstrip('/')) if conf.path else 0
+        else:
+            database = 0
         return RedisSettings(
             host=conf.hostname or 'localhost',
             port=conf.port or 6379,