Add documentation about Time Tracking

doc/workflow/README.md

@@ -23,6 +23,7 @@
 - [Slash commands](../user/project/slash_commands.md)
 - [Sharing a project with a group](share_with_group.md)
 - [Share projects with other groups](share_projects_with_other_groups.md)
+- [Time tracking](time_tracking.md)
 - [Two-factor Authentication (2FA)](two_factor_authentication.md)
 - [Web Editor](../user/project/repository/web_editor.md)
 - [Releases](releases.md)

doc/workflow/time_tracking.md

+# Time Tracking
+
+> Introduced in GitLab 8.14.
+
+Time Tracking lets teams stack their project estimates against their time spent.
+
+Other interesting links:
+
+- [Time Tracking landing page on about.gitlab.com][landing]
+
+## Overview
+
+Time Tracking lets you
+* record the time spent working on an issue or a merge request,
+* add an estimate of the amount of time needed to complete an issue or a merge
+request.
+
+You don't have to indicate an estimate to enter the time spent, and vice versa.
+
+Data about time tracking is shown on the issue/merge request sidebar, as shown
+below.
+
+![Time tracking in the sidebar](time-tracking/time-tracking-sidebar.png)
+
+## How to enter data
+
+Time Tracking uses two [slash commands] that GitLab introduced with this new
+feature: `/spend` and `/estimate`.
+
+Slash commands can be used in the body of an issue or a merge request, but also
+in a comment in both an issue or a merge request.
+
+Below is an example of how you can use those new slash commands inside a comment.
+
+![Time tracking example in a comment](time-tracking/time-tracking-example.png)
+
+Adding time entries (time spent or estimates) is limited to project members.
+
+### Estimates
+
+To enter an estimate, write `/estimate`, followed by the time. For example, if
+you need to enter an estimate of 3 days, 5 hours and 10 minutes, you would write
+`/estimate 3d 5h 10m`.
+
+Every time you enter a new time estimate, any previous time estimates will be
+overridden by this new value. There should only be one valid estimate in an
+issue or a merge request.
+
+To remove an estimation entirely, use `/remove_estimation`.
+
+### Time spent
+
+To enter a time spent, use `/spend 3d 5h 10m`.
+
+Every new time spent entry will be added to the current total time spent for the
+issue or the merge request.
+
+You can remove time by entering a negative amount: `/spend -3d` will remove 3
+days from the total time spent. You can't go below 0 minutes of time spent,
+so GitLab will automatically reset the time spent if you remove a larger amount
+of time compared to the time that was entered already.
+
+To remove all the time spent at once, use `/remove_time_spent`.
+
+## Configuration
+
+The following time units are available:
+* weeks (w)
+* days (d)
+* hours (h)
+* minutes (m)
+
+Default conversion rates are 1w = 5d and 1d = 8h.
+
+[landing]: https://about.gitlab.com/features/time-tracking
+[slash-commands]: ../user/project/slash_commands.md