Add new createTransaction method

frontend/src/app/Services/auth.service.ts

@@ -11,12 +11,25 @@ const httpOptions = {
 })
 export class AuthService {
   constructor(private http: HttpClient) {}
+
+  /**
+   * @param  {string} email
+   * @param  {string} password
+   * @returns Observable
+   */
   login(email: string, password: string): Observable<any> {
     return this.http.post(AUTH_API + '/login', {
       email,
       password,
     });
   }
+
+  /**
+   * @param  {string} email
+   * @param  {string} username
+   * @param  {string} password
+   * @returns Observable
+   */
   register(email: string, username: string, password: string): Observable<any> {
     return this.http.post(
       AUTH_API + '/register',