feat: implement complete CMT backend with API endpoints and test suite

- Add 7 core API endpoints: users, transactions, partners, products, inventory, payments, credit
- Implement role-based authentication (admin/write/read-only access)
- Add comprehensive database models with proper relationships
- Include full test coverage for all endpoints and business logic
- Set up Alembic migrations and Docker configuration
- Configure FastAPI app with CORS and database integration

backend/app/schemas/models.py

@@ -14,12 +14,11 @@ The models include:
 - Inventory
 """
 
-from sqlmodel import SQLModel, Field, UniqueConstraint
+from sqlmodel import SQLModel, Field
 from datetime import datetime, date
-from sqlalchemy import Column, DateTime, func, Enum as SQLEnum
-from enum import Enum
+from sqlalchemy import Column, String, CheckConstraint, DateTime, func, Enum as SQLEnum
 from typing import Optional
-from base import UserRole, PartnerType, TransactionType, TransactionStatus, PaymentMethod
+from .base import UserRole, PartnerType, TransactionType, TransactionStatus, PaymentMethod
 
 
 class User(SQLModel, table=True):
@@ -157,7 +156,7 @@ class Transaction_details(SQLModel, table=True):
 
     id: Optional[int] = Field(default=None, primary_key=True)
     partner_id: int = Field(nullable=False, foreign_key="partner.id")
-    product_id: str = Field(nullable=False, foreign_key="product.id")
+    product_id: int = Field(nullable=False, foreign_key="product.id")
     qty: int = Field(nullable=False)
     selling_price: int = Field(nullable=False)
 
@@ -193,11 +192,12 @@ class Payment(SQLModel, table=True):
 
     id: Optional[int] = Field(default=None, primary_key=True)
     transaction_id: int = Field(nullable=False, foreign_key="transactions.id")
-    payment_method: PaymentMethod = Field(
+    payment_method: str = Field(
         sa_column=Column(
-            SQLEnum(PaymentMethod),
+            String(10),
+            CheckConstraint("payment_method IN ('momo', 'bank', 'cash')"),
             nullable=False,
-            default=PaymentMethod.CASH
+            default="cash"
         )
     )
     paid_amount: int = Field(nullable=False)