Update v2 NPM installation instructions

Author: GeoffreyBooth

docs/v2/index.html

@@ -671,7 +671,7 @@
 <p>The golden rule of CoffeeScript is: <em>“It’s just JavaScript.”</em> The code compiles one-to-one into the equivalent JS, and there is no interpretation at runtime. You can use any existing JavaScript library seamlessly from CoffeeScript (and vice-versa). The compiled output is readable, pretty-printed, and tends to run as fast or faster than the equivalent handwritten JavaScript.</p>
 <p><strong>Latest Version:</strong> <a href="http://github.com/jashkenas/coffeescript/tarball/2.0.0-alpha1">2.0.0-alpha1</a></p>
 <blockquote>
-<pre><code>npm install -g coffeescript</code></pre></blockquote>
+<pre><code>npm install -g coffeescript@next</code></pre></blockquote>
 
         <h2>Overview</h2><p><em>CoffeeScript on the <span class="hidden-md-up">top</span><span class="hidden-sm-down">left</span>, compiled JavaScript output on the <span class="hidden-md-up">bottom</span><span class="hidden-sm-down">right</span>. The CoffeeScript is editable!</em></p>
 <aside class="code-example container-fluid bg-ribbed-dark" data-example="overview">
@@ -771,10 +771,10 @@ <h2>CoffeeScript 2</h2><p>CoffeeScript 2 generates JavaScript that uses the late
         <h2>Installation</h2><p>The command-line version of <code>coffee</code> is available as a <a href="http://nodejs.org/">Node.js</a> utility. The <a href="v2/browser-compiler/coffeescript.js">core compiler</a> however, does not depend on Node, and can be run in any JavaScript environment, or in the browser (see <a href="#try">Try CoffeeScript</a>).</p>
 <p>To install, first make sure you have a working copy of the latest stable version of <a href="http://nodejs.org/">Node.js</a>. You can then install CoffeeScript globally with <a href="http://npmjs.org">npm</a>:</p>
 <blockquote>
-<pre><code>npm install --global coffeescript</code></pre></blockquote>
+<pre><code>npm install --global coffeescript@next</code></pre></blockquote>
 <p>When you need CoffeeScript as a dependency of a project, within that project’s folder you can install it locally:</p>
 <blockquote>
-<pre><code>npm install --save coffeescript</code></pre></blockquote>
+<pre><code>npm install --save coffeescript@next</code></pre></blockquote>
 
       </section>
       <section id="usage">