Added GitHub handles to the README

README.md

@@ -9,10 +9,10 @@ tracker.
 ## Contact Details
-| Name             | Role   | Email                   | GitLab.com     | Slack          |
-|:-----------------|:-------|:------------------------|:---------------|:---------------|
-| Yorick Peterse   | Mentor | <yorick@gitlab.com>     | @yorickpeterse | @yorickpeterse |
-| Heather McNamee  | Coach  | <heather@gitlab.com>    | @nearlythere   | @heather       |
-| Grzegorz Bizon   | Coach  | <grzegorz@gitlab.com>   | @grzesiek      | @grzegorz      |
-| Tomasz Maczukin  | Coach  | <tomasz@gitlab.com>     | @tmaczukin     | @tmaczukin     |
-| Piotr Szotkowski | Coach  | <chastell@chastell.net> | ...            | ...            |
+| Name             | Role   | Email                   | GitLab.com     | Slack          | GitHub         |
+|:-----------------|:-------|:------------------------|:---------------|:---------------|:---------------|
+| Yorick Peterse   | Mentor | <yorick@gitlab.com>     | @yorickpeterse | @yorickpeterse | @YorickPeterse |
+| Heather McNamee  | Coach  | <heather@gitlab.com>    | @nearlythere   | @heather       | @nearlythere   |
+| Grzegorz Bizon   | Coach  | <grzegorz@gitlab.com>   | @grzesiek      | @grzegorz      | @grzesiek      |
+| Tomasz Maczukin  | Coach  | <tomasz@gitlab.com>     | @tmaczukin     | @tmaczukin     | @tmaczukin     |
+| Piotr Szotkowski | Coach  | <chastell@chastell.net> | ...            | ...            | ...            |