only show contributors whose team is not nil – either sponsored or volunteer
only show contributors whose team is not nil – either sponsored or volunteer

michaelem/rgsoc-teams,michaelem/rgsoc-teams,TeamCheesy/rgsoc-teams,rails-girls-summer-of-code/rgsoc-teams,rails-girls-summer-of-code/rgsoc-teams,michaelem/rgsoc-teams,TeamCheesy/rgsoc-teams,TeamCheesy/rgsoc-teams,rails-girls-summer-of-code/rgsoc-teams