feat(activities): Add Activity models

activities/models.py

@@ -0,0 +1,32 @@
+from django.db import models
+
+
+class ActivitySeries(models.Model):
+    """
+    A series of related :class:`Activity`s
+    """
+    
+    class Meta:
+        verbose_name_plural = 'activity series'
+
+    #: Name of activity series
+    name = models.CharField(max_length=1023,
+                            blank=False, null=False)
+
+
+class Activity(models.Model):
+    """
+    An instance of an activity - e.g. a workshop
+    """
+    
+    class Meta:
+        verbose_name_plural = 'activities'
+
+    #: Name of activity
+    name = models.CharField(max_length=1023,
+                            blank=False, null=False)
+
+    #: Optional :class:`ActivitySeries` to which this activity belongs
+    series = models.ForeignKey(ActivitySeries, related_name='instances',
+                               on_delete=models.PROTECT,
+                               blank=True, null=True)