Added shelter.txt

Been dealing with a lot of changes lately because of the two moons. :moon: :moon: = :frowning:  I decided to make a floor plan for a shelter. The file is named `shelter.txt`. Let me know what you think about the dimensions @draculaonmars  and  @mummyonmars

Please note on line 3 and 4 are the dimensions for each of your bedrooms. I figured you both don't need that much space since you sleep in coffin/sarcophagus.
 
Any feedback is welcome! 
:heart: **@wolfmanonmars** :wolf: