Merge pull request #2 from d10/master

Improve `README.md`

README.md

@@ -1,22 +1,44 @@
-Nodejs git.io module
-====================
+# `gitio`
 
-A simple module to call the [git.io url shortner service](https://github.com/blog/985-git-io-github-url-shortener) with
-nodejs, the module returns a simple object with the status code and URL if created.
+A Node.js module to call GitHub's [git.io url shortener service](https://github.com/blog/985-git-io-github-url-shortener).
 
-Usage
------
+## Usage
 
-    var gitio = require('gitio');
+```js
+var gitio = require('gitio');
 
-    // Pass a direct URL and get back a random URL
-    gitio('https://github.com/tanepiper/node-gitio', function(err, result) {
-      if (err) throw err;
-      console.log(result);
-    });
+// Pass a direct URL and get back a random URL
+gitio('https://github.com/tanepiper/node-gitio', function(err, result) {
+  if (err) throw err;
+  console.log(result);
+});
 
-    // Pass an optional key to get the URL of your request
-    gitio('https://github.com/joyent/node', 'nodejs', function(err, result) {
-      if (err) throw err;
-      console.log(result);
-    });
+// Pass an optional key to get the URL of your request
+gitio('https://github.com/joyent/node', 'nodejs', function(err, result) {
+  if (err) throw err;
+  console.log(result);
+});
+```
+
+## API
+
+### gitio(url, [code], cb)
+
+#### url
+
+Type: `string`
+
+The `github.com` URL to shorten.
+
+#### code
+
+Type: `string`
+
+The shortened URL path.
+
+#### callback(err, url)
+
+Type: `function`
+
+A callback invoked with two arguments; an error object if an error occurred,
+and the shortened URL.