Update UsingOtherPlugins.md

docs/UsingOtherPlugins.md

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+# Using Other Plugins from ScriptCraft
+The following question gets asked a lot so I'm going to try to answer it here:
 
+> How to use other bukkit plugins API?  
+> Like PermissionEX API.  
+> I can check permission group by java code:  
+> ru.tehkode.permissions.bukkit.PermissionsEx.getUser(player).inGroup("moderator");  
+> But I can't run this code in JavaScript.  
+> -- [Bukkit forum question][1]  
+
+[1]: http://dev.bukkit.org/bukkit-plugins/scriptcraft/?page=2#c48
+
+The above question refers to using ScriptCraft for CraftBukkit so I'll answer that first:
+
+You can get the permissionsEx (or any other plugin) like this...
+```javascript
+var pex = server.pluginManager.getPlugin('PermissionsEx');
+if (pex.getUser(player).inGroup('moderator') ) {
+...
+}
+```
+Generally if you want to use another plugin's API, then get the plugin object by name and then call its methods. In the above example the `pex` variable refers to the aforementioned `PermissionsEx` Plugin. Once you have that reference you can call any of the plugin's methods just as you would in Java. The tricky part is getting the reference and that's where `server.pluginManager.getPlugin()` comes in.