Only trigger add_status_task when status is first created

I think the reason I didn't do this initially was so that related users
and books, which are added necessarily after the model instance is
crated, will be part of the object when the task runs, but I have
investigated this and because of the transaction.atomic statement in the
to_model method in bookwyrm/activitypub/base_activity.py and in the
status view (added in this commit), this is not an issue.

bookwyrm/views/status.py

@@ -6,6 +6,7 @@ from urllib.parse import urlparse
 from django.contrib.auth.decorators import login_required
 from django.core.validators import URLValidator
 from django.core.exceptions import ValidationError
+from django.db import transaction
 from django.db.models import Q
 from django.http import HttpResponse, HttpResponseBadRequest, Http404
 from django.shortcuts import get_object_or_404, redirect
@@ -56,6 +57,7 @@ class CreateStatus(View):
         return TemplateResponse(request, "compose.html", data)
 
     # pylint: disable=too-many-branches
+    @transaction.atomic
     def post(self, request, status_type, existing_status_id=None):
         """create status of whatever type"""
         created = not existing_status_id
@@ -83,7 +85,6 @@ class CreateStatus(View):
             return redirect_to_referer(request)
 
         status = form.save(request, commit=False)
-        status.ready = False
         # save the plain, unformatted version of the status for future editing
         status.raw_content = status.content
         if hasattr(status, "quote"):
@@ -123,7 +124,6 @@ class CreateStatus(View):
         if hasattr(status, "quote"):
             status.quote = to_markdown(status.quote)
 
-        status.ready = True
         status.save(created=created)
 
         # update a readthrough, if needed