Added OTP model for password reset system

Author: Uttam Singh

backend/app/models/otp.py

@@ -0,0 +1,11 @@
+from sqlalchemy import Column, Integer, String, DateTime
+from datetime import datetime, timedelta
+from app.database import Base
+
+class OtpModel(Base):
+    __tablename__ = "otp_records"
+
+    id = Column(Integer, primary_key=True, index=True)
+    email = Column(String, index=True, nullable=False)
+    otp = Column(String, nullable=False)
+    expires_at = Column(DateTime, default=lambda: datetime.utcnow() + timedelta(minutes=10))