Add "Language"

[giosce]

The crawler already retrieve through github API the "language" value of a repository.
For repo that have "language" I see its value in the snapshot/v1 branch.
https://github.com/codeforamerica/brigade-project-index/blob/snapshot/v1/projects/BetaNYC/Boundaries-Map.toml

But I can't find the code that create the index/v1 toml file which as of now contains only a few fields from the snapshot toml.
https://github.com/codeforamerica/brigade-project-index/blob/index/v1/projects/BetaNYC/Boundaries-Map.toml