Add world-exit to documentation

docs/maps.en.md

@@ -19,6 +19,7 @@ This tutorial is "work in progess", hence its worth checking it from time to tim
 * 2020-12-16: New URL scheme, test instance now at: https://test.visit.at.wa-test.rc3.cccv.de/_/global/<your_map_url_here> (adapt your CORS headers if needed!)
 * 2020-12-17: Audio: removed external URLs. **IMPORTANT:** If you want to include streams please contact us!
 * 2020-12-20: Starter kit added.
+* 2020-12-22: World-Exit added.
 
 ## Known Bugs
 Following bugs are known and worked on:
@@ -81,6 +82,10 @@ A map may consist of any number of tile layers. Your map needs a start layer whi
 
 ![](img/layer.png)
 
+#### World Exit
+We recommend the following tile for your exit(s) back to the lobby map for a more consistent user experience.
+![](https://tiles.rc3.world/structures/worldExit.png)
+(It's up to you to follow this recommendation)
 
 #### Highlight current layer
 For a better mapping experience, highlight the current layer: