POSIX-compliant deploy function

deploy.sh

function deploy {
  deploy_dir=/home/telmo/Development/deploy-scripts

  if [ $1 = "frontend" ] || [ $1 = "front" ] || [ $1 = "f" ]; then
    sh "$deploy_dir/deploy_frontend.sh"
  elif [ $1 = "backend" ] || [ $1 = "back" ] || [ $1 = "b" ]; then
    sh "$deploy_dir/deploy_backend.sh"
  else
    (>&2 echo "ERROR: \"$1\" doesn't match any known parameter.")
    return 1
  fi
}