Add a 'clear_db' management command to drop our tables (zephyr + sessions).

(imported from commit 5763983689448944bed13feeeae9a482908a7aff)

zephyr/management/commands/clear_db.py

@@ -0,0 +1,15 @@
+from django.core.management.base import NoArgsCommand
+
+from django.contrib.auth.models import User
+from zephyr.models import Zephyr, UserProfile, ZephyrClass, Recipient
+from django.contrib.sessions.models import Session
+
+class Command(NoArgsCommand):
+    help = "Clear only tables we change: zephyr + sessions"
+
+    def handle_noargs(self, **options):
+        for klass in [Zephyr, ZephyrClass, UserProfile, User, Recipient]:
+            klass.objects.all().delete()
+        Session.objects.all().delete()
+
+        self.stdout.write("Successfully cleared the database.\n")