Fix crashes

tournaments/models/match.py

@@ -45,17 +45,22 @@ class Match(models.Model):
         if self.start_date:
             return self.start_date.strftime("%H:%M")
         else:
-            return "no date"
+            return ''
         # return str(self.start_date) #.strftime("%H:%M")
 
     def current_duration(self):
         if self.end_date:
             return (self.end_date - self.start_date).total_seconds()
-        else:
+        elif self.start_date:
             return (timezone.now() - self.start_date).total_seconds()
+        else:
+            return 0
 
     def started(self):
-        return timezone.now() > self.start_date
+        if self.start_date:
+            return timezone.now() > self.start_date
+        else:
+            return False
 
     def durationPrefix(self):
         if self.current_duration() > 0: