Add backend requirements.txt

backend/requirements.txt

@@ -0,0 +1,9 @@
+fastapi==0.104.1
+uvicorn[standard]==0.24.0
+sqlalchemy==2.0.23
+python-jose[cryptography]==3.3.0
+passlib[bcrypt]==1.7.4
+python-multipart==0.0.6
+pydantic==2.5.0
+pydantic-settings==2.1.0
+python-dotenv==1.0.0