fix thread.js not passing 'since' correctly to post updates api

app/routes/threads.py

@@ -31,7 +31,6 @@ def thread(slug):
             ("thread_id", "=", thread.id),
             ("id", "<=", after_id),
         ])
-        print(post_position)
         page = math.ceil((post_position) / POSTS_PER_PAGE)
     else:
         page = max(1, min(page_count, int(request.args.get("page", default = 1))))

data/static/js/thread.js

@@ -64,7 +64,7 @@
 
   function tryFetchUpdate() {
     if (!threadEndpoint) return;
-    const body = JSON.stringify({since: now});
+    const body = JSON.stringify({'since': now});
     fetch(threadEndpoint, {method: "POST", headers: {"Content-Type": "application/json"}, body: body})
       .then(res => res.json())
       .then(json => {