order thinks on the front page by time of last edit

instead of time of creation

thinks/views.py

@@ -4,6 +4,7 @@ from django.http import HttpResponse, JsonResponse
 from django.shortcuts import render, redirect
 from django.views import generic
 from django.urls import reverse
+from django.utils.timezone import now
 from itertools import groupby
 import json
 import mimetypes
@@ -41,7 +42,7 @@ class IndexView(ThinkMixin, generic.ListView):
 
         context['templates'] = Think.objects.filter(is_template=True)
 
-        context['recent_thinks'] = Think.objects.filter(is_template=False).order_by('-creation_time')[:3]
+        context['recent_thinks'] = Think.objects.all().order_by('-last_edited', '-creation_time')[:3]
 
         context['thinks'] = sorted(Think.objects.filter(is_template=False), key=lambda t: (t.category if t.category else '', -t.creation_time.timestamp()))
 
@@ -100,6 +101,9 @@ class ThinkView(ThinkMixin, generic.DetailView):
 
         think = self.object
 
+        think.last_edited = now()
+        think.save(update_fields=('last_edited',))
+
         root = think.root
 
         strpath = self.request.GET.get('path')