Readme: link to the usage wiki

Change-Id: I2728d04f1e5135c3babae3c1837c1da2fd08f80c
Signed-off-by: Michele Carignani <michele.carignani@etsi.org>

Readme.md

@@ -32,6 +32,8 @@ To create a new TDL model by means of the TDLan2 textual representation for **st
 
 To translate a TDL model from the TDLan2 textual representation to the **XF format** (or the other way around) open the source model and press the <code>T</code> icon on the toolbar. The resulting model shall be stored in the same folder as the source model with the type of the model (`.tdlan2` or `.tdl`) appended to the name of the source model.
 
+More information on using the plugins is available at [Usage wiki](https://tdl.etsi.org/wiki/index.php/Usage).
+
 ## Setting up a local environment for development and testing
 
  * Install following additional components