missing file / broken link

Hi. Quick note that the link in the README.Md to Introduction.Rmd at the 'The intro lesson' bullet returns a 404.
[https://github.com/school-of-data/r-consortium-proposal/blob/master/material/lessons/Introduction.Rmd](https://github.com/school-of-data/r-consortium-proposal/blob/master/material/lessons/Introduction.Rmd)
