Shopping List always duplicates the first item

[rrash283]

Version

Please provide your current version (can be found on the system page since v0.8.4)
Version:

Bug description

The first ingredient added to the ingredient list will have an index of 0. If that same ingredient is used again in it assigns index = 0
if index: when index = 0 returns False so the ingredient is added to the list again.
The code needs to be changed to something like if index is not None:

The code below is from the shopping list view.

for r in recipes:
        for ri in RecipeIngredient.objects.filter(recipe=r).exclude(unit__name__contains='Special:').all():
            index = None
            for x, ig in enumerate(ingredients):
                if ri.ingredient == ig.ingredient and ri.unit == ig.unit:
                    index = x

            if index:
                ingredients[index].amount = ingredients[index].amount + ri.amount
            else:
                ingredients.append(ri)

[vabene1111]

thanks for the detailed report! the shopping list really need a rework, this is another reason why #114