fix(backend): 🐛 fix error when assigning favorite recipe

mealie/db/models/_model_utils.py

@@ -102,7 +102,7 @@ def auto_init(exclude: Union[set, list] = None):  # sourcery no-metrics
                         if len(val) > 0 and isinstance(val[0], dict):
                             val = [elem.get("id") for elem in val]
 
-                        instances = [relation_cls.get_ref(elem, session=session) for elem in val]
+                        instances = [x for x in [relation_cls.get_ref(elem, session=session) for elem in val] if x]
                         setattr(self, key, instances)
 
             return init(self, *args, **kwargs)

mealie/db/models/recipe/recipe.py

@@ -73,6 +73,9 @@ class RecipeModel(SqlAlchemyBase, BaseMixins):
     favorited_by_id = sa.Column(sa.Integer, sa.ForeignKey("users.id"))
     favorited_by = orm.relationship("User", back_populates="favorite_recipes")
 
+    class Config:
+        get_attr = "slug"
+
     @validates("name")
     def validate_name(self, key, name):
         assert name != ""