Backend finished

Co-authored-by: Álvaro <alvaro6gv@users.noreply.github.com>

backend/app/schemas/user.py

@@ -0,0 +1,31 @@
+from pydantic import BaseModel, Field
+from typing import Optional
+
+# POST /login
+class UserLogin(BaseModel):
+    user_name: str
+    password: str
+
+# POST /register
+class UserRegister(BaseModel):
+    user_name: str
+    password: str
+
+# POST /2fa
+class User2FA(BaseModel):
+    user_name: str
+    pre_auth_token: str
+    totp_code: str
+    
+# POST /enable-2fa
+class Token2FA(BaseModel):
+    token: str
+
+# GET /users
+# GET /users/{user_id}
+class UserRead(BaseModel):
+    user_id: int
+    user_name: str
+    
+    class Config:
+        from_attributes = True