fix for not saving related model in reverse rel

docs/relations/foreign-key.md

@@ -99,7 +99,7 @@ course = Course(name="Math", completed=False) # note - not saved
 await department.courses.add(course)
 assert course.pk is not None # child model was saved
 # relation on child model is set and FK column saved in db
-assert courses.department == department
+assert course.department == department
 # relation on parent model is also set
 assert department.courses[0] == course 
 ```
@@ -112,6 +112,10 @@ assert department.courses[0] == course
     
     That means that in example above the department has to be saved before you can call `department.courses.add()`.
 
+!!!warning
+    This method will not work on `ManyToMany` relations - there, both sides of the relation have to be saved before adding to relation.
+    
+
 ### remove
 
 Removal of the related model one by one.

docs/releases.md

@@ -8,10 +8,13 @@
 ## 🐛 Fixes
 
 * Fix is null filter with pagination and relations (by @erichaydel) [#214](https://github.com/collerek/ormar/issues/214)
+* Fix not saving child object on reverse side of the relation if not saved before [#216](https://github.com/collerek/ormar/issues/216)
+
 
 ## 💬 Other
 
 * Expand [fastapi](https://collerek.github.io/ormar/fastapi) part of the documentation to show samples of using ormar in requests and responses in fastapi.
+* Improve the docs in regard of `default`, `ForeignKey.add` etc. 
 
 # 0.10.9
 

ormar/relations/relation_proxy.py

@@ -214,7 +214,7 @@ class RelationProxy(Generic[T], list):
             setattr(self._owner, self.field_name, item)
         else:
             setattr(item, relation_name, self._owner)
-            await item.update()
+            await item.upsert()
         await self._owner.signals.post_relation_add.send(
             sender=self._owner.__class__,
             instance=self._owner,

tests/test_queries/test_adding_related.py

@@ -0,0 +1,54 @@
+from typing import Optional
+
+import databases
+import pytest
+import sqlalchemy
+import asyncio
+
+import ormar
+
+from tests.settings import DATABASE_URL
+
+database = databases.Database(DATABASE_URL)
+metadata = sqlalchemy.MetaData()
+
+
+class Department(ormar.Model):
+    class Meta:
+        database = database
+        metadata = metadata
+
+    id: int = ormar.Integer(primary_key=True)
+    name: str = ormar.String(max_length=100)
+
+
+class Course(ormar.Model):
+    class Meta:
+        database = database
+        metadata = metadata
+
+    id: int = ormar.Integer(primary_key=True)
+    name: str = ormar.String(max_length=100)
+    completed: bool = ormar.Boolean(default=False)
+    department: Optional[Department] = ormar.ForeignKey(Department)
+
+
+@pytest.fixture(autouse=True, scope="module")
+def create_test_database():
+    engine = sqlalchemy.create_engine(DATABASE_URL)
+    metadata.drop_all(engine)
+    metadata.create_all(engine)
+    yield
+    metadata.drop_all(engine)
+
+
+@pytest.mark.asyncio
+async def test_adding_relation_to_reverse_saves_the_child():
+    async with database:
+        department = await Department(name="Science").save()
+        course = Course(name="Math", completed=False)
+
+        await department.courses.add(course)
+        assert course.pk is not None
+        assert course.department == department
+        assert department.courses[0] == course