Update index.md
Update index.md

There are no communities on data.gov. Also simplified language.
portofsandiego/project-open-data.github.io,portofsandiego/project-open-data.github.io,portofsandiego/project-open-data.github.io,bpushed/project-open-data.github.io,pjdufour/project-open-data.github.io,portofsandiego/project-open-data.github.io,Chuck8080/opendata,pjdufour/project-open-data.github.io,judecalvillo/project-open-data.github.io,bpushed/project-open-data.github.io,Chuck8080/opendata,pjdufour/project-open-data.github.io,pjdufour/project-open-data.github.io,judecalvillo/project-open-data.github.io