Track specific task or diff activities.

[WangSiyuan]

Track specifc task or diff. And push activities to the slack.

Usage

@phabribot track {{ObjectId(Txxx, Dxxx, #xxxx)}} // start track task or diff or project.
@phabribot track stop {{Txxx, Dxxx, #xxxx}} // stop track
@phabribot tracks // list current track list.