The solution is to use a bug tracker within the SCM:
http://bugseverywhere.org/ (my personal favorite, but there are 3/4 other options that you can look into).
Not only it does offer distributed bug tracking on the command line (without breaking your workflow), but it implicitly allows to isolate bugs to branches. You can fix a bug in a branch, and a subsequent merge of the changeset will automatically fix the current branch.
I don't understand why these projects are so underrated. In "early git times", distributed bug tracking on top of git was quite a hot subject. They solve many issues nicely.
Github might be a "nifty" viewer, and I do host projects on github for added visibility (by simply using a second push remote), but that's about it. I find "tig" and "bugseverywhere" to complement git nicely and work much better than any web browser could.
The issue tracker is not, unfortunately, but neither are most issue trackers.