add fixes for fastapi model clones, add functionality to add and remove models to relation, add relation proxy, fix all tests, adding values also to pydantic model __dict__some refactors

tests/test_model_definition.py

@@ -54,7 +54,9 @@ class ExampleModel2(Model):
 
 @pytest.fixture()
 def example():
-    return ExampleModel(pk=1, test_string="test", test_bool=True, test_decimal=decimal.Decimal(3.5))
+    return ExampleModel(
+        pk=1, test_string="test", test_bool=True, test_decimal=decimal.Decimal(3.5)
+    )
 
 
 def test_not_nullable_field_is_required():
@@ -110,6 +112,7 @@ def test_sqlalchemy_table_is_created(example):
 
 def test_no_pk_in_model_definition():
     with pytest.raises(ModelDefinitionError):
+
         class ExampleModel2(Model):
             class Meta:
                 tablename = "example3"
@@ -120,6 +123,7 @@ def test_no_pk_in_model_definition():
 
 def test_two_pks_in_model_definition():
     with pytest.raises(ModelDefinitionError):
+
         class ExampleModel2(Model):
             class Meta:
                 tablename = "example3"
@@ -131,6 +135,7 @@ def test_two_pks_in_model_definition():
 
 def test_setting_pk_column_as_pydantic_only_in_model_definition():
     with pytest.raises(ModelDefinitionError):
+
         class ExampleModel2(Model):
             class Meta:
                 tablename = "example4"
@@ -141,6 +146,7 @@ def test_setting_pk_column_as_pydantic_only_in_model_definition():
 
 def test_decimal_error_in_model_definition():
     with pytest.raises(ModelDefinitionError):
+
         class ExampleModel2(Model):
             class Meta:
                 tablename = "example5"
@@ -151,6 +157,7 @@ def test_decimal_error_in_model_definition():
 
 def test_string_error_in_model_definition():
     with pytest.raises(ModelDefinitionError):
+
         class ExampleModel2(Model):
             class Meta:
                 tablename = "example6"