initial plugins docs content

Author: fpliger

docs/user-guide/plugins.md

@@ -1,3 +1,16 @@
 # Plugins
 
-** TODO: Finish this **
+PyScript, like many other software plaforms, offers a Plugin API that can be used to extend its
+own functionality without the need to modify its own core. By using this API, users can add new
+features and distribute them as plugins.
+
+At the moment, PyScript supports plugins written in Javascript. These plugins can use PyScript
+Plugins API to define entry points and hooks so that the plugin can be collected and hook into
+the PyScript lifecycle events, with the ablity to modify and integrate the features of PyScript
+core itself.
+
+Here's an example of how a PyScript plugin looks like:
+
+```js
+
+```