bugfix: moving of tasks in tree now works as intended

Signed-off-by: Stephan Richter <s.richter@srsoftware.de>

frontend/src/routes/task/Add.svelte

@@ -2,7 +2,7 @@
     import { onMount }       from 'svelte';
     import { useTinyRouter } from 'svelte-tiny-router';
 
-    import { api, get }      from '../../urls.svelte.js';
+    import { api, get, post }      from '../../urls.svelte.js';
     import { error, yikes }  from '../../warn.svelte';
     import { t }             from '../../translations.svelte.js';
     import { user }          from '../../user.svelte.js';
@@ -104,11 +104,7 @@
 
     async function saveTask(){
         const url  = api('task/add');
-        const resp = await fetch(url,{
-            credentials : 'include',
-            method      : 'POST',
-            body        : JSON.stringify(task)
-        });
+        const resp = await post(url,task);
         if (resp.ok) {
             localStorage.removeItem(`task/${task.id}/description`);
             if (!assignee) { // if assignee is set, this form was opened within an external context. hence we don`t want to navigate somewhere else!