Improve README.md according to review
Improve README.md according to review

Clarify that scripts "gae-run-app.sh" and "setup_datastore.sh" need to
be run in Person Finder Docker container's SHELL

gimite/personfinder,clobrano/personfinder,google/personfinder,google/personfinder,gimite/personfinder,google/personfinder,clobrano/personfinder,clobrano/personfinder,gimite/personfinder,AwesomeTurtle/personfinder,AwesomeTurtle/personfinder,AwesomeTurtle/personfinder,gimite/personfinder,google/personfinder