feat(backend): added auth, reviews, users modules

also provided tests

src/backend/api/v1/schemas.py

@@ -2,12 +2,10 @@ from datetime import datetime
 from typing import Any
 
 from ninja import Schema
-from pydantic import ConfigDict, Field
+from pydantic import Field
 
 
 class FieldError(Schema):
-    model_config = ConfigDict(populate_by_name=True)
-
     field: str = Field(
         ...,
         description="Field name with error (can be nested)",
@@ -19,8 +17,6 @@ class FieldError(Schema):
 
 
 class ApiError(Schema):
-    model_config = ConfigDict(populate_by_name=True)
-
     code: str
     message: str
     trace_id: str = Field(..., alias="traceId")