Add CRUD operations for users with tests and fixtures

Implemented user CRUD operations including creation, retrieval, updating, and deletion through a generic CRUD base class. Enhanced user schemas with additional attributes and created tests to verify functionality, covering edge cases such as duplicates and pagination. Updated the test suite with new fixtures and methods to support the tests.

backend/app/schemas/users.py

@@ -4,7 +4,6 @@ from datetime import datetime
 from typing import Optional, Dict, Any
 from uuid import UUID
 
-import pydantic
 from pydantic import BaseModel, EmailStr, field_validator, ConfigDict
 
 
@@ -27,6 +26,7 @@ class UserBase(BaseModel):
 
 class UserCreate(UserBase):
     password: str
+    is_superuser: bool = False
 
     @field_validator('password')
     @classmethod
@@ -46,7 +46,7 @@ class UserUpdate(BaseModel):
     last_name: Optional[str] = None
     phone_number: Optional[str] = None
     preferences: Optional[Dict[str, Any]] = None
-
+    is_active: Optional[bool] = True
     @field_validator('phone_number')
     def validate_phone_number(cls, v: Optional[str]) -> Optional[str]:
         if v is None:
@@ -81,7 +81,6 @@ class UserUpdate(BaseModel):
         return cleaned
 
 
-
 class UserInDB(UserBase):
     id: UUID
     is_active: bool
@@ -147,4 +146,4 @@ class LoginRequest(BaseModel):
 
 
 class RefreshTokenRequest(BaseModel):
-    refresh_token: str
+    refresh_token: str