Merge branch 'keyboard_shortcuts' into 'master'

Keyboard shortcuts

Added doc about how to view keyboard shortcuts

cc/ @sytse

See merge request !1829

doc/workflow/README.md

@@ -13,4 +13,5 @@
 - [Project importing from GitLab.com to your private GitLab instance](import_projects_from_gitlab_com.md)
 - [Protected branches](protected_branches.md)
 - [Change your time zone](timezone.md)
+- [Keyboard shortcuts](shortcuts.md)
 - [Web Editor](web_editor.md)
\ No newline at end of file

doc/workflow/shortcuts.md

+# GitLab keyboard shortcuts
+
+You can see GitLab's keyboard shortcuts by using 'shift + ?'
+
+![Shortcuts](shortcuts.png)
\ No newline at end of file