Add screenshot to README

README.md

@@ -5,6 +5,8 @@ This mod follows in the footsteps of the useful [Extended Placement] mod for
 as optics and doors easily, without having to cycle through all possible
 rotations every time.
 
+![Screenshot](docs/screenshot.png)
+
 Rotating a node can be done in three ways:
 
 - Click near the center of a face, and the node rotates 90° around it.