Rake task to switch sites that Pow serves

pow.rake

# This is for instances where a single Rails app serves multiple domains.
# That is, http://domainA.com and http://domainB.com are both served by the same Rails app.
# When launching these manually, I specify which site I want to see by passing a site variable:
# site=domainB ruby script/server
# This gist allows site switching via a rake task:
# rake pow[SITENAME]
# If no '[SITENAME]' is provided, then it defaults to the 'domainA' site

desc "Switches site that Pow serves"
task :pow, :site_name do |t, args|
  pow_config = "#{Rails.root}/.powrc"
  args.with_defaults(:site_name => "domainA")
  
  # Overwrite the .powrc file with the new site name
  file = File.open(pow_config, 'w')
  file.write <<EOF
if [ -f "$rvm_path/scripts/rvm" ] && [ -f ".rvmrc" ]; then
  source "$rvm_path/scripts/rvm"
  source ".rvmrc"
fi

export site=#{args.site_name}
EOF
  
  # Restart Pow
  FileUtils.touch "#{Rails.root}/tmp/restart.txt"
  
  # Display the site change
  puts "Switched to #{args.site_name}"
end