Revert "Merge pull request #1215 from Elegios/composer_use_category_id"

This reverts commit 763859d4396f406352c4901502a8c33430e54cb2, reversing
changes made to b62caf80fbb81ea7a8ece5632513fcc8559db0e1.
Merge branch 'master' of github.com:discourse/discourse