small bug fixes

boatmovers/models.py

@@ -93,13 +93,17 @@ class Race(models.Model):
         return self.name
 
     def save(self, *args, **kwargs):
-        results = self.results.all()
         crews = []
         athletes = []
-        for result in results:
-            crews.append(result.crew.id)
-            for athlete in result.crew.athletes.all():
-                athletes.append(athlete.id)
+
+        try:
+            results = self.results.all()
+            for result in results:
+                crews.append(result.crew.id)
+                for athlete in result.crew.athletes.all():
+                    athletes.append(athlete.id)
+        except ValueError:
+            pass
 
         if len(crews) != len(set(crews)):
             raise ValidationError(