run gem install as part of ruby build.
update gems version.

Note for sequel gem. it does not work with 3.48.0 or later versions.
so we use 3.47.0. need to fix after_initialize() hook and the model
classes using single table inheritance plugin.
use https in Gemfiles.
use modified eventmachine from github.com/axsh/eventmachine.git.
upgrade ruby binary to p448.
git pull if ruby-build.git is available locally.
Merge pull request #221 from axsh/monthly-bundle-update

Monthly bundle update: 13/Jul