adding release page, updating version to install in instructions

Author: vsoch

_posts/releases/2017-06-26-release-2-3-1.md

@@ -0,0 +1,16 @@
+---
+title:  "Singularity 2.3.1 Security Release"
+category: releases
+permalink: "release-2-3-1"
+version: "2.3.1"
+---
+
+<a target="_blank" href="https://github.com/singularityware/singularity/releases/tag/2.3.1">This release</a> includes a fix for a High Severity security issue on older hosts, and other improvements and fixes to previous versions of Singularity. 
+
+## Security Information:
+
+A potential escalation pathway was identified that could have allowed a malicious user to escalate their privileges on hosts that do not support the `PR_SET_NO_NEW_PRIVS` flag for the `prctl()` system call. This release fixes this as well as several other identified bugs and potential race conditions.
+
+Please report any additional bugs to <a target="_blank" href="https://github.com/singularityware/singularity/issues/new">our issues board.</a>
+
+Thanks to the hard work of all our contributers to nail this bug in the butt!

pages/docs/install/install-linux.md

@@ -13,10 +13,10 @@ You can try the following two options:
 ### Option 1: Download latest stable release
 You can always download the latest tarball release from <a href="{{ site.repo }}/releases" target="_blank">Github</a>
 
-For example, here is how to download version `2.3` and install:
+For example, here is how to download version `2.3.1` and install:
 
 ```bash
-VERSION=2.3
+VERSION=2.3.1
 wget https://github.com/singularityware/singularity/releases/download/$VERSION/singularity-$VERSION.tar.gz
 tar xvf singularity-$VERSION.tar.gz
 cd singularity-$VERSION