Add utils for jwt

utils/jwt.py

-from authlib.jose import jwt
+import jwt
 
 
 def generate_jwt(user_id):
-    header = {'alg': 'RS256'}
-    payload = {'iss': 'Authlib', 'sub': '123', 'user_id': user_id}
-    key = "SOME_KEY".encode()
-    return jwt.encode(header, payload, key)
+    encoded = jwt.encode({'user_id': user_id}, 'secret', algorithm='HS256')
+    return encoded.decode()
+
+
+def decode_jwt(jwt_token):
+    return jwt.decode(jwt_token, 'secret', algorithms=['HS256'])