actually fixed https://github.com/sagemathinc/smc/issues/677 --  it should not be possible to add any collaborator on the project that contains a course as a student to that course
actually fixed https://github.com/sagemathinc/smc/issues/677 --  it should not be possible to add any collaborator on the project that contains a course as a student to that course

tscholl2/smc,DrXyzzy/smc,sagemathinc/smc,tscholl2/smc,sagemathinc/smc,sagemathinc/smc,tscholl2/smc,DrXyzzy/smc,DrXyzzy/smc,tscholl2/smc,sagemathinc/smc,tscholl2/smc,DrXyzzy/smc