added a router for logistics, now creating label

backend/app/models.py

@@ -1,6 +1,7 @@
-from sqlalchemy import Column, Integer, String, Date, ForeignKey, JSON
+from sqlalchemy import Column, Integer, String, Date, ForeignKey, JSON, Interval, DateTime, Boolean
 from sqlalchemy.orm import relationship
 from app.database import Base
+from datetime import datetime, timedelta
 import uuid
 
 
@@ -130,3 +131,23 @@ class Sample(Base):
     # Foreign keys and relationships
     puck_id = Column(Integer, ForeignKey('pucks.id'))
     puck = relationship("Puck", back_populates="samples")
+
+class Slot(Base):
+    __tablename__ = "slots"
+    id = Column(String, primary_key=True, index=True)
+    occupied = Column(Boolean, default=False)
+    needs_refill = Column(Boolean, default=False)
+    time_until_refill = Column(Interval, nullable=True)
+    last_refill = Column(DateTime, default=datetime.utcnow)
+
+
+class LogisticsEvent(Base):
+    __tablename__ = "logistics_events"
+    id = Column(Integer, primary_key=True, index=True, autoincrement=True)
+    dewar_id = Column(Integer, ForeignKey('dewars.id'), nullable=False)
+    slot_id = Column(String, ForeignKey('slots.id'), nullable=True)
+    event_type = Column(String, nullable=False)
+    timestamp = Column(DateTime, default=datetime.utcnow)
+
+    dewar = relationship("Dewar")
+    slot = relationship("Slot")