Update 2018-03-20-tractenberg-summary.md
Update 2018-03-20-tractenberg-summary.md

making link a link
ErinBecker/datacarpentry.github.io,datacarpentry/datacarpentry.github.io,datacarpentry/datacarpentry.github.io,ErinBecker/datacarpentry.github.io,ErinBecker/datacarpentry.github.io,ErinBecker/datacarpentry.github.io,datacarpentry/datacarpentry.github.io