Add gender to stock detail report so that we are able to view how much womens stock we have available rather than having excessive department categories (e.g. Mens this, Womens that)

We can then see top level we have X mountain bikes for example, and should we wish to look deeper than this we can filter by gender to see that we have X womens mountain bikes. In reality, gender is not crucial to top-level data as a bike may only be deemed "womens" because it has a cross bar when we all know full well that those arent only suitable for women... We'd like to be able to tell how many mountain bikes we have for example as a whole without having to add to figures together manually each time. But also have the flexibility to look at this in more detail with the addition of the gender column!