first working version where transactions can be stored

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

frontend/src/urls.svelte.js

@@ -35,7 +35,7 @@ export function post(url,data){
     return fetch(url,{
         credentials : 'include',
         method      : 'POST',
-        body        : JSON.stringify(data)
+        body        : typeof data === 'string' ? data : JSON.stringify(data)
     });
 }