перенос миграций с alembic

src/domain/external_channel.py

@@ -22,9 +22,8 @@ class ExternalChannel(TimestampedModel):
         'models.User', related_name='external_channels', on_delete=fields.CASCADE, index=True
     )
 
-    target_channels: fields.ManyToManyRelation['TargetChannel']
-
     if TYPE_CHECKING:
+        target_channels: fields.ManyToManyRelation['TargetChannel']
         user_id: UUID
 
     class Meta:

src/domain/target_channel.py

@@ -32,6 +32,8 @@ class TargetChannel(TimestampedModel):
         'models.ExternalChannel',
         related_name='target_channels',
         through='target_external_channel',
+        forward_key='external_channel_id',
+        backward_key='target_channel_id',
     )
 
     if TYPE_CHECKING: