Could not find a JavaScript runtime
$ bundle exec rake db:migrate
rake aborted!
Could not find a JavaScript runtime. See https://github.com/sstephenson/execjs for a list of available runtimes.
(See full trace by running task with --trace)
推荐下面的网址
https://github.com/joyent/node/wiki/installing-node.js-via-package-manager
$curl -sL https://rpm.nodesource.com/setup | bash -
$yum install -y nodejs