Plugin howto added again

README.md

@@ -10,6 +10,48 @@
 
 <!-- /BADGES -->
 
+## How to use the plugin
+
+* First, you need to create a Javascript file inside your Docpad project.
+You must create that as a NodeJS module. Check the next example:
+
+``` javascript
+module.exports = function (opts, baseApiUrl) {
+  var server = opts.server
+
+  server.get(baseApiUrl + '/test', function (req, res, next) {
+    return res.json({
+      test: 'OK'
+    })
+  })
+
+  server.get(baseApiUrl + '/bbbb', function (req, res, next) {
+    var err = new Error()
+    next(err)
+  })
+}
+```
+
+* Finally, you have to put the path of the file in Docpad configuration file:
+
+``` coffee-script
+# DocPad Configuration File
+# http://docpad.org/docs/config
+
+# Define the DocPad Configuration
+docpadConfig = {
+  # Plugins configuration
+  plugins:
+    api:
+      baseApiUrl: '/APIURLTEST'
+      source: [
+        file: 'api/api-test.js'
+        ]
+}
+
+# Export the DocPad Configuration
+module.exports = docpadConfig
+```
 
 <!-- INSTALL/ -->