Is it possible to add a Katakana course for Japanese to go alongside the Hiragana course?
Just as my post says, would it be possible to add a course for Katakana?
Katakana is already in the course, it just doesn't have separate lessons for it. It gradually appears in later lessons. As new loan words are introduced, katakana syllabes and signs needed to write them are introduced too. By the time you finish the tree, you will see them all :)