+
+ If a prebuilt docker package is not available for your platform, the
+ short instructions for installing it are:
+
+ 1. Create a `docker` group and add yourself to it.
+
+ <pre>
+ $ sudo addgroup docker
+ $ sudo adduser `whoami` docker
+ </pre>
+
+ Log out and back in.
+
+ 2. Add a `cgroup` filesystem and mount it:
+
+ <pre>
+ $ mkdir -p /cgroup
+ $ grep cgroup /etc/fstab
+ none /cgroup cgroup defaults 0 0
+ $ sudo mount /cgroup
+ </pre>
+
+ 3. [Download and run a docker binary from docker.io.](http://docs.docker.io/en/latest/installation/binaries/)
+
+* Ruby (version 1.9.3 or greater)