[Suggestion] Add IV-V-vi (or minor VI-VII-i) to the Progressions page

VI-VII-i is a REALLY common progression in minor keys, but because all of the chords on the Progressions page are in relative major, it gets shifted to IV-V-vi in its relative major, and relegated to simply the “Beginner” category.

It would be nice and interesting to see how VI-VII-i (minor) can occur in different songs.