update README.md

Author: ilsanbao

README.md

@@ -2,4 +2,24 @@
 IPIP.net officially supported IP database ipdb format parsing library
 
 # Installing
-composer install ipip/db
+composer install ipip/db
+
+# Example Code
+<code>
+<pre>
+$db = new ipip\db\Reader('c:\tmp\ipdb\mydata6vipday4.ipdb');
+$loc = $db->find("2001:250:200::");
+$map = $db->findMap("2001:250:200::");
+$obj = $db->findInfo("2001:250:200::");
+var_dump($loc, $map, $obj);
+
+try
+{
+    var_dump($db->find("255.255.255.1"));
+}
+catch (Exception $e)
+{
+    exit($e->getMessage());
+}
+</pre>
+</code>