refactor: improve database initialization and news fetching structure

frontend/src/components/CronSlider.vue

@@ -12,7 +12,7 @@ onMounted(async () => {
 async function update() {
   saving.value = true;
   await fetch('/settings/cron', {
-    method: 'PUT',
+    method: 'POST',
     headers: {'Content-Type': 'application/json'},
     body: JSON.stringify({hours: hours.value})
   });