added child endpoint, ability to add and edit child as well as auto redirect to add-child page when user without child accesses home page

src/baby_monitor/models/db/child.py

@@ -0,0 +1,28 @@
+"""Child database model."""
+
+from typing import TYPE_CHECKING
+from sqlalchemy import Column, Integer, String, DateTime, Float, ForeignKey
+from datetime import datetime
+
+if TYPE_CHECKING:
+    from sqlalchemy.orm import DeclarativeBase
+
+    Base = DeclarativeBase
+else:
+    from baby_monitor.repositories.dependencies.get_database import Base
+
+
+class Child(Base):
+    """Child database model."""
+
+    __tablename__ = "children"
+
+    id = Column(Integer, primary_key=True, index=True)
+    name = Column(String, nullable=False)
+    birth_time = Column(DateTime, nullable=False)
+    birth_weight = Column(Float, nullable=False)  # in grams
+    user_id = Column(Integer, ForeignKey("users.id"), nullable=False)
+    created_at = Column(DateTime, default=datetime.utcnow, nullable=False)
+
+    def __repr__(self) -> str:
+        return f"<Child(id={self.id}, name='{self.name}', user_id={self.user_id})>"