(Heroku/GIT) Comments added to commit command not appearing in activity

facebook git heroku commit

One way would be to customizing the message of one of the Heroku Deploy hooks.
I remember having done so more than 2 years ago in "Git email hook to include commit message and changed files".

It’s possible to use variables when defining the message, title or subject of any deploy hook attribute.

git_log

log of commits between this deploy and the last