Mac(Yosemite)でRuby 2.1.5 インストール

$ ~/.rbenv/plugins/ruby-build

$ git pull
remote: Counting objects: 12, done.
remote: Compressing objects: 100% (11/11), done.
remote: Total 12 (delta 3), reused 0 (delta 0)
Unpacking objects: 100% (12/12), done.
From git://github.com/sstephenson/ruby-build
   d22a320..ae0f2b9  master     -> origin/master
 * [new tag]         v20141113  -> v20141113
Merge made by the 'recursive' strategy.
 bin/ruby-build              | 2 +-
 share/ruby-build/1.9.3-p551 | 2 ++
 share/ruby-build/2.0.0-p598 | 2 ++
 share/ruby-build/2.1.5      | 2 ++
 4 files changed, 7 insertions(+), 1 deletion(-)
 create mode 100644 share/ruby-build/1.9.3-p551
 create mode 100644 share/ruby-build/2.0.0-p598
 create mode 100644 share/ruby-build/2.1.5

$ rbenv install 2.1.5
Downloading ruby-2.1.5.tar.gz...
-> http://dqw8nmjcqpjn7.cloudfront.net/4305cc6ceb094df55210d83548dcbeb5117d74eea25196a9b14fa268d354b100
Installing ruby-2.1.5...
Installed ruby-2.1.5 to /Users/masuyama/.rbenv/versions/2.1.5

$ rbenv global 2.1.5

$ gem install bundler
Fetching: bundler-1.7.6.gem (100%)
Successfully installed bundler-1.7.6
1 gem installed

$ ruby -v
ruby 2.1.5p273 (2014-11-13 revision 48405) [x86_64-darwin14.0]

いまのところRailsアプリの挙動に問題なし