feat: add first database migration

backend/hermes/app/db/database.py

@@ -26,4 +26,5 @@ def get_db():
     try:
         yield db
     finally:
-        db.close()
+        db.close()
+        import app.models.user

backend/hermes/app/models/user.py

@@ -0,0 +1,26 @@
+from sqlalchemy import String
+from sqlalchemy.orm import Mapped
+from sqlalchemy.orm import mapped_column
+
+from app.db.database import Base
+
+
+class User(Base):
+    __tablename__ = "users"
+
+    id: Mapped[int] = mapped_column(primary_key=True)
+
+    username: Mapped[str] = mapped_column(
+        String(50),
+        unique=True,
+        index=True
+    )
+
+    email: Mapped[str] = mapped_column(
+        String(255),
+        unique=True
+    )
+
+    password_hash: Mapped[str] = mapped_column(
+        String(255)
+    )