feature: use default value for created_at field in db entities

backend/app/infrastructure/database/allocations.py

@@ -155,8 +155,6 @@ def get_user_alloc_sum_by_epoch(epoch: int, user_address: str) -> int:
 def store_allocation_request(
     user_address: str, epoch_num: int, request: UserAllocationRequestPayload, **kwargs
 ):
-    now = datetime.utcnow()
-
     user: User = get_by_address(user_address)
 
     options = {"is_manually_edited": None, **kwargs}
@@ -168,7 +166,6 @@ def store_allocation_request(
             nonce=request.payload.nonce,
             proposal_address=to_checksum_address(a.proposal_address),
             amount=str(a.amount),
-            created_at=now,
         )
         for a in request.payload.allocations
     ]
@@ -187,16 +184,13 @@ def store_allocation_request(
 
 @deprecated("Alloc rework")
 def add_all(epoch: int, user_id: int, nonce: int, allocations):
-    now = datetime.utcnow()
-
     new_allocations = [
         Allocation(
             epoch=epoch,
             user_id=user_id,
             nonce=nonce,
             proposal_address=to_checksum_address(a.proposal_address),
             amount=str(a.amount),
-            created_at=now,
         )
         for a in allocations
     ]

backend/app/infrastructure/database/models.py

@@ -1,7 +1,7 @@
-from datetime import datetime as dt
 from typing import Optional
 
 from app.extensions import db
+from app.modules.common import time
 
 # Alias common SQLAlchemy names
 Column = db.Column
@@ -12,7 +12,7 @@
 
 class BaseModel(Model):
     __abstract__ = True
-    created_at = Column(db.TIMESTAMP, default=dt.utcnow)
+    created_at = Column(db.TIMESTAMP, default=lambda: time.now().datetime())
 
 
 class User(BaseModel):