Bad links in training event display
1. Go to https://amy.software-carpentry.org/workshops/trainings?page=2
2. Click on any of the links that supposedly lead to a training event.
3. 404

I understand why we want to retain this view - it's helpful to look at summary stats - but:
1. The links need to resolve.
2. We need to be able to sort chronologically with most recent first.

diff --git a/workshops/templates/workshops/all_trainings.html b/workshops/templates/workshops/all_trainings.html
index 5bd230fb..2067f9e3 100644
--- a/workshops/templates/workshops/all_trainings.html
+++ b/workshops/templates/workshops/all_trainings.html
@@ -12,7 +12,7 @@
       </tr>
       {% for training in all_trainings %}
       <tr>
-        <td><a href="{% url 'event_details' training.event %}">{{ training.event__slug }}</a></td>
+        <td><a href="{% url 'event_details' training.event__slug %}">{{ training.event__slug }}</a></td>
         <td>{{ training.trainees }}</td>
         <td>{{ training.finished }}</td>
       </tr>
diff --git a/workshops/views.py b/workshops/views.py
index f5b9881d..df43e3a7 100644
--- a/workshops/views.py
+++ b/workshops/views.py
@@ -1847,7 +1847,7 @@ def all_trainings(request):
         .values('event').annotate(finished=Count('person'))
     finished = {f['event']: f['finished'] for f in finished}
 
-    trainings = Task.objects.filter(role=learner).filter(event__tags=ttt).order_by('event__start') \
+    trainings = Task.objects.filter(role=learner).filter(event__tags=ttt).order_by('-event__start') \
         .values('event', 'event__slug').annotate(trainees=Count('person'))
     for t in trainings:
         event_id = t['event']
['workshops/views.py', 'workshops/templates/workshops/all_trainings.html']