Add gif previews

Author: kriskbx

preview/reports.gif

@@ -12,6 +12,10 @@ gtt monitors the time you spent on an issue or merge request locally and syncs i
 It also allows you to create reports in various formats from time tracking data
 stored on GitLab.
 
+![Monitor your time](https://raw.githubusercontent.com/kriskbx/gitlab-time-tracker/master/preview/tracking.gif)
+
+![Get a report](https://raw.githubusercontent.com/kriskbx/gitlab-time-tracker/master/preview/reports.gif)
+
 ## contents
 
 * [requirements](#requirements)