feed categories and subcategories

[rizumu]

At the moment 'Music' is hard wired.

Let try the solution of adding a category model, it can have a foreign key to itself to iteslf to implement the hierarchy.

class Category(models.Model):
    title = models.CharField(_("title"), max_length=255)
    slug = AutoSlugField(_("slug"), populate_from="title")
    parent = models.ForeignKey("self", blank=True, null=True, related_name="child")