fixes -- in dates and the lack of the preshow

docker-compose.jsonnet

@@ -97,7 +97,7 @@
 
   // The spreadsheet id and worksheet names for sheet sync to act on
   sheet_id:: "your_id_here",
-  worksheets:: ["Day %d" % n for n in std.range(1, 7)],
+  worksheets:: ["Tech Test & Preshow"] + ["Day %d" % n for n in std.range(1, 7)],
 
   // Now for the actual docker-compose config
 

sheetsync/sheetsync/main.py

@@ -84,6 +84,8 @@ class SheetSync(object):
 
 	def parse_bustime(self, value):
 		"""Convert from HH:MM or HH:MM:SS format to datetime"""
+		if value.strip() == '--':
+			return None
 		bustime = common.parse_bustime(value)
 		return common.bustime_to_dt(self.bustime_start, bustime)