VS2013 and Github: current branch does not have upstream bra

I often work with VS2013 and Github. first i create a repository in github and then open vs2013 and create a new project.

after creating new project in vs2013 i add it to source control where a dialog comes and i select git option. i then commit the changes and publist with my github project url.

this way it always work but last two days when i try to publish my project from VS2013 to github then i am getting error current branch does not have upstream branch configured

so here i am attaching two screen shot.

i am very new in git and github. so share instruction details how to fix this problem.