mention how to open the settings frame

Author: jsb

README.md

@@ -14,6 +14,8 @@ and choose an appropriate button. This can be any keyboard or mouse button.
 Open the RingMenu by clicking the summon button anywhere on the screen. You can now drag and drop actions to the slots of the RingMenu like for a regular action bar.
 
 ## Configuration
+Open the settings window by typing **/ringmenu**.
+
 Using the _First Button Slot_ and _Number of Buttons_ settings, you can adjust the range of action button slots that are used for the RingMenu. Depending on your class, some button slot ranges might be already in use for shapeshift forms. Use [this list](http://wowwiki.wikia.com/wiki/ActionSlot) to pick an appropriate range.
 
 Further configuration options include the radius and angle of the RingMenu as well as the color of the transparent backdrop.