feat: add subscription and transaction repositories

- Implemented SubscriptionRepository with methods to get, create, and update subscriptions.
- Added BalanceTXRepository for creating and retrieving balance transactions.
- Introduced a test script for simulating Pally webhook for local testing.

repositories/users.py

@@ -1,7 +1,10 @@
+import datetime
+
 from sqlalchemy import select
 from sqlalchemy.ext.asyncio import AsyncSession
 
 from db.models import User
+from db.models.transactions import BalanceTransaction, BalanceTxType
 from schemas.users import NewUserDTO
 
 
@@ -61,12 +64,60 @@ class UserRepository:
         return user
 
     async def increase_user_balance(
-        self, session: AsyncSession, user_id: int, amount: int
+        self,
+        session: AsyncSession,
+        user_id: int,
+        amount: int,
+        tx_type: BalanceTxType,
+        description: str,
     ) -> User | None:
         user = await self.get_user_by_id(session, user_id=user_id)
         if not user:
             return None
+
+        created_at = datetime.datetime.now(datetime.UTC)
+        transaction = BalanceTransaction(
+            user_id=user_id,
+            amount=amount,
+            tx_type=tx_type,
+            balance_before=user.balance,
+            balance_after=user.balance + amount,
+            description=description,
+            created_at=created_at,
+        )
+
         user.balance += amount
 
+        session.add(transaction)
+
+        await session.commit()
+        return user
+
+    async def decrease_user_balance(
+        self,
+        session: AsyncSession,
+        user_id: int,
+        amount: int,
+        tx_type: BalanceTxType,
+        description: str,
+    ) -> User | None:
+        user = await self.get_user_by_id(session, user_id=user_id)
+        if not user or user.balance < amount:
+            return None
+
+        created_at = datetime.datetime.now(datetime.timezone.UTC)
+        transaction = BalanceTransaction(
+            user_id=user_id,
+            amount=amount,
+            tx_type=tx_type,
+            balance_before=user.balance,
+            balance_after=user.balance + amount,
+            description=description,
+            created_at=created_at,
+        )
+
+        user.balance -= amount
+        session.add(transaction)
+
         await session.commit()
         return user