Change label of mutation to be consistent

frontend/api/model.js

@@ -122,7 +122,7 @@ export default class OpenAppStackModel {
   deleteUser(username){
     const vars = { username: username };
     const deleteUser = `
-        mutation editUser($username: String!){
+        mutation deleteUser($username: String!){
           deleteUser(
             username: $username
           ){