Add "get_user" method to the base runner class.
Add "get_user" method to the base runner class.

This method returns a username of user who triggered the action execution.

StackStorm/st2,pixelrebel/st2,peak6/st2,lakshmi-kannan/st2,nzlosh/st2,nzlosh/st2,emedvedev/st2,StackStorm/st2,pixelrebel/st2,punalpatel/st2,peak6/st2,Plexxi/st2,StackStorm/st2,Plexxi/st2,tonybaloney/st2,lakshmi-kannan/st2,punalpatel/st2,nzlosh/st2,StackStorm/st2,Plexxi/st2,peak6/st2,tonybaloney/st2,emedvedev/st2,Plexxi/st2,tonybaloney/st2,emedvedev/st2,lakshmi-kannan/st2,nzlosh/st2,punalpatel/st2,pixelrebel/st2