Front: Type authentication string for more clarity

front/models/AuthToken.ts

@@ -0,0 +1,3 @@
+type AuthToken = string;
+
+export default AuthToken;

front/state/UserSlice.ts

@@ -1,12 +1,13 @@
 import { createSlice, PayloadAction } from '@reduxjs/toolkit';
+import AuthToken from '../models/AuthToken';
 
 export const userSlice = createSlice({
   name: 'user',
   initialState: {
-	token: undefined as string | undefined
+	token: undefined as AuthToken | undefined
   },
   reducers: {
-    setUserToken: (state, action: PayloadAction<string>) => {
+    setUserToken: (state, action: PayloadAction<AuthToken>) => {
       state.token = action.payload;
     },
     unsetUserToken: (state) => {