add percentage property method

gwift/wish/models.py

@@ -44,6 +44,15 @@ class Wish(models.Model):
         i.save()
         return i
 
+    @property
+    def percentage(self):
+        """
+        Calcule le pourcentage de complétion pour un élément.
+        """
+        number_of_linked_parts = Part.objects.filter(wish=self).count()
+        total = self.number_of_parts * self.numbers_available
+        percentage = (number_of_linked_parts / total)
+        return percentage * 100
 
 class Part(models.Model):
     wish = models.ForeignKey('Wish')