docs: Added recommendation to use jCenter dependency for Volley

Bug: 27170930
Change-Id: I4c542c7031b89f527f757c76b6cf3ed196fe6f45

docs/html/training/volley/index.jd

@@ -42,7 +42,7 @@ faster. Volley is available through the open
 <li>Automatic scheduling of network requests.</li>
 <li>Multiple concurrent network connections.</li>
 <li>Transparent disk and memory response caching with standard HTTP
-<a href=http://en.wikipedia.org/wiki/Cache_coherence">cache coherence</a>.</li>
+<a href="http://en.wikipedia.org/wiki/Cache_coherence">cache coherence</a>.</li>
 <li>Support for request prioritization.</li>
 <li>Cancellation request API. You can cancel a single request, or you can set blocks or
 scopes of requests to cancel.</li>
@@ -66,13 +66,22 @@ alternative like {@link android.app.DownloadManager}.</p>
 <a href="https://android.googlesource.com/platform/frameworks/volley">AOSP</a>
 repository at {@code frameworks/volley} and contains the main request dispatch pipeline
 as well as a set of commonly applicable utilities, available in the Volley "toolbox." The
-easiest way to add Volley to your project is to clone the Volley repository and set it as
-a library project:</p>
+easiest way to add Volley to your project is to add the following dependency to your app's
+build.gradle file:
+
+<pre class="no-pretty-print">
+dependencies {
+    ...
+    compile 'com.android.volley:volley:1.0.0'
+}
+</pre>
+
+You can also clone the Volley repository and set it as a library project:</p>
 
 <ol>
 <li>Git clone the repository by typing the following at the command line:
 
-<pre>
+<pre class="no-pretty-print">
 git clone https://android.googlesource.com/platform/frameworks/volley
 </pre>
 </li>