Add Germany to travel destinations.

Author: Bob Reis (breis)

english/travel-destinations/travel-destinations.md

@@ -6,6 +6,9 @@ It's Summer! Time to explore these places:
 
 [Sweden](https://youtu.be/5KYm1UpXiq0?t=53s)
 
+Visit the Rhine and Rothenburg
+[Germany](https://www.youtube.com/watch?v=uD9b7mP6whk)
+
 Fall is a great season to take a vacation in any of these spots:
 [fall destinations](fall/fall.md)