Make by_weekday nullable, update rrule help_text

program/models.py

@@ -280,25 +280,7 @@ class Schedule(models.Model):
         RRule,
         on_delete=models.CASCADE,
         related_name="schedules",
-        help_text=dedent(
-            """
-            A recurrence rule.
-
-            * 1 = once,
-            * 2 = daily,
-            * 3 = business days,
-            * 4 = weekly,
-            * 5 = biweekly,
-            * 6 = every four weeks,
-            * 7 = every even calendar week (ISO 8601),
-            * 8 = every odd calendar week (ISO 8601),
-            * 9 = every 1st week of month,
-            * 10 = every 2nd week of month,
-            * 11 = every 3rd week of month,
-            * 12 = every 4th week of month,
-            * 13 = every 5th week of month
-            """
-        ),
+        help_text="A recurrence rule."
     )
     show = models.ForeignKey(
         Show,
@@ -317,6 +299,7 @@ class Schedule(models.Model):
             (5, "Saturday"),
             (6, "Sunday"),
         ],
+        null=True
     )
     first_date = models.DateField(help_text="Start date of schedule.")
     start_time = models.TimeField(help_text="Start time of schedule.")