default for em_type and coinc_far = null

gracedb/superevents/migrations/0005_add_coinc_far_and_em_type.py

@@ -21,6 +21,6 @@ class Migration(migrations.Migration):
         migrations.AddField(
             model_name='Superevent',
             name='em_type',
-            field=models.CharField(blank=True, default=b'', max_length=100),
+            field=models.CharField(null=True, blank=True, max_length=100),
         ),
     ]

gracedb/superevents/models.py

@@ -113,8 +113,8 @@ class Superevent(CleanSaveModel, AutoIncrementModel):
     is_exposed = models.BooleanField(default=False)
 
     # New O3b fields for RAVEN:
-    coinc_far = models.FloatField(null=True, blank=True)
-    em_type = models.CharField(blank=True, default=b'', max_length=100)
+    coinc_far = models.FloatField(null=False, blank=True)
+    em_type = models.CharField(blank=True, null=True, max_length=100)
 
     # Meta class --------------------------------------------------------------
     class Meta: