Add introduction

Author: iHiD

bootcamp_content/projects/drawing/exercises/structured-house/introduction.md

@@ -22,6 +22,8 @@ As a reminder, the house should continue to look like this:
 ### House Instructions
 
 - The top-left of the drawing canvas is `0,0`. The bottom-right is `100,100`.
+- The sky fills the canvas (from `0,0` to `100,100`).
+- The grass is full width (from `0` to `100`) sits on the bottom of the canvas at `100` with a height of `20`.
 - The frame of the house (the big rectangle) should be 60 wide and 40 height. It should have it's top-left corner at 20x50.
 - The roof sits snuggly on top of the house's frame. It should overhang the left and right of the house by 4 on each side. It should have a height of 20, and it's point should be centered horizontally (50).
 - The windows are both the same size, with have a width of 12 and a height of 13. They both sit 5 from the top of the house frame, and 10 inset from the sides.