Indexing course run end and enrollment_end fields

ECOM-5559 and ECOM-5440

course_discovery/apps/course_metadata/migrations/0026_auto_20160912_2146.py

+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('course_metadata', '0025_remove_program_category'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='courserun',
+            name='end',
+            field=models.DateTimeField(null=True, db_index=True, blank=True),
+        ),
+        migrations.AlterField(
+            model_name='courserun',
+            name='enrollment_end',
+            field=models.DateTimeField(null=True, db_index=True, blank=True),
+        ),
+        migrations.AlterField(
+            model_name='historicalcourserun',
+            name='end',
+            field=models.DateTimeField(null=True, db_index=True, blank=True),
+        ),
+        migrations.AlterField(
+            model_name='historicalcourserun',
+            name='enrollment_end',
+            field=models.DateTimeField(null=True, db_index=True, blank=True),
+        ),
+    ]

course_discovery/apps/course_metadata/models.py

@@ -346,9 +346,9 @@ class CourseRun(TimeStampedModel):
         help_text=_(
             "Title specific for this run of a course. Leave this value blank to default to the parent course's title."))
     start = models.DateTimeField(null=True, blank=True)
-    end = models.DateTimeField(null=True, blank=True)
+    end = models.DateTimeField(null=True, blank=True, db_index=True)
     enrollment_start = models.DateTimeField(null=True, blank=True)
-    enrollment_end = models.DateTimeField(null=True, blank=True)
+    enrollment_end = models.DateTimeField(null=True, blank=True, db_index=True)
     announcement = models.DateTimeField(null=True, blank=True)
     short_description_override = models.CharField(
         max_length=255, default=None, null=True, blank=True,