Run either foreman, `rails server` (Rails 3) or `script/server` (Rails 2) based what's in the file system

rails_server.sh

function s()
{
  # Look for a .env file, run foreman with -p 3000 for consistency
  if [ -e ".env" ]
  then
    foreman start -p 3000
  # Look for "script/rails" (Rails 3)
  elif [ -e "script/rails" ]
  then
    script/rails server
  # Faillback to Rails 2
  else
    script/server
  fi
}