Added install section

Author: hsbt

en/documentation/installation/index.md

@@ -28,6 +28,7 @@ The following overview lists available installation methods
 for different needs and platforms.
 
 * [Package Management Systems](#package-management-systems)
+  * [Snap](#snap)
   * [Debian, Ubuntu](#apt)
   * [CentOS, Fedora, RHEL](#yum)
   * [Gentoo](#portage)
@@ -63,6 +64,24 @@ older versions of Ruby in their official repositories. If you would like to
 use the newest Ruby, make sure you use the correct package name,
 or use the tools described further below instead.
 
+### snap (Ubuntu or other linux distribution)
+{: #snap}
+
+snap is the package system developed by Canonical.
+You can use it like this.
+
+{% highlight sh %}
+$ sudo snap install ruby --classic
+{% endhighlight %}
+
+You can also use multiple channels. The following commands switch to Ruby 2.3:
+
+{% highlight sh %}
+$ sudo snap switch ruby --channel=2.3/stable
+$ sudo snap refresh
+{% endhighlight %}
+
+snap should install the latest stable Ruby version.
 
 ### apt (Debian or Ubuntu)
 {: #apt}