fix: save and send cookie in dev setup

client/src/app/services/api.ts

@@ -7,20 +7,20 @@ import Transaction from '@model/transaction'
   providedIn: 'root',
 })
 export class APIService {
-  private apiUrl = 'http://localhost:3000/api' 
+  private apiUrl = '/api';
   private isAuthenticatedSubject = new BehaviorSubject<boolean>(false);
   isAuthenticated$ = this.isAuthenticatedSubject.asObservable();
   
   constructor(private http: HttpClient){}
 
   getTransactions(): Observable<Transaction[]>{
-    return this.http.get<Transaction[]>(this.apiUrl + '/transactions');
+    return this.http.get<Transaction[]>(`${this.apiUrl}/transactions`);
   }
   login(username: string, password: string): Observable<any>{
-    return this.http.post(this.apiUrl + '/auth/login',{ 'username': username, 'password': password});
+    return this.http.post(`${this.apiUrl}/auth/login`,{ 'username': username, 'password': password});
   }
   logout(): Observable<any>{
-    return this.http.post(this.apiUrl + '/auth/logout', {});
+    return this.http.post(`${this.apiUrl}/auth/logout`, {});
   }
   checkAuthStatus(): Observable<boolean> {
     return this.http.get(`${this.apiUrl}/auth/status`, { withCredentials: true}).pipe(