Only build on master
Only build on master

jupyter/nbgrader,modulexcite/nbgrader,ellisonbg/nbgrader,alope107/nbgrader,jupyter/nbgrader,EdwardJKim/nbgrader,alope107/nbgrader,ellisonbg/nbgrader,jupyter/nbgrader,jhamrick/nbgrader,jupyter/nbgrader,dementrock/nbgrader,EdwardJKim/nbgrader,jdfreder/nbgrader,dementrock/nbgrader,jupyter/nbgrader,EdwardJKim/nbgrader,ellisonbg/nbgrader,MatKallada/nbgrader,EdwardJKim/nbgrader,MatKallada/nbgrader,jdfreder/nbgrader,modulexcite/nbgrader,ellisonbg/nbgrader,jhamrick/nbgrader,jhamrick/nbgrader,jhamrick/nbgrader