implemented adding positions to document

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

frontend/src/routes/document/View.svelte

@@ -71,6 +71,7 @@
             body:JSON.stringify(selected)
         });
         if (resp.ok){
+            doc.positions = await resp.json();
         } else {
             error = await resp.text();
         }