create Gameboard class

[dealingwith]

closes #37

Gameboard just extends Matrix

is this even necessary/useful?

[dealingwith]

adding an attr_accessor for height and width to the Gameboard class, then using gameboard.height and gameboard.width breaks everything--why?

gameboard.rb

class Gameboard < Matrix
   # matrix is installed when you install ruby, 
   # no need to use gem. 
   # docs: https://ruby-doc.org/stdlib-2.5.1/libdoc/matrix/rdoc/Matrix.html
+  attr_accessor :height, :width
 end

game.rb:

-    @gameboard_height = gameboard_height
-    @gameboard_width = gameboard_width
     @gameboard = Gameboard.zero(gameboard_height, gameboard_width)
-    @squares = Gameboard.zero(gameboard_height, gameboard_width)
+    @gameboard.height = gameboard_height
+    @gameboard.width = gameboard_width
+    @squares = Matrix.zero(gameboard_height, gameboard_width)

     create_tetromino()
   end
@@ -36,13 +36,13 @@ class Game
   end

   def create_tetromino()
-    @tetromino = Tetromino.new(@gameboard, @tetromino_shapes.sample, [0, 0], @gameboard_height, @gameboard_width)
+    @tetromino = Tetromino.new(@gameboard, @tetromino_shapes.sample, [0, 0], @gameboard.height, @gameboard.width)
     @gameboard = tetromino.put_tetromino(@gameboard, [0, 0], tetromino.width, tetromino.height)
   end

   def draw(start_pos, size) # size is the side length of a square
-    (0...@gameboard_width).each do |i|
-      (0...@gameboard_height).each do |j|
+    (0...@gameboard.width).each do |i|
+      (0...@gameboard.height).each do |j|
         if @squares[j, i] != 0

Traceback (most recent call last):
    10: from tetris.rb:44:in `<main>'
     9: from /Users/danielmiller/.rbenv/versions/2.7.0/lib/ruby/gems/2.7.0/gems/ruby2d-0.10.0/lib/ruby2d/dsl.rb:39:in `show'
     8: from /Users/danielmiller/.rbenv/versions/2.7.0/lib/ruby/gems/2.7.0/gems/ruby2d-0.10.0/lib/ruby2d/window.rb:619:in `show'
     7: from /Users/danielmiller/.rbenv/versions/2.7.0/lib/ruby/gems/2.7.0/gems/ruby2d-0.10.0/lib/ruby2d/window.rb:619:in `ext_show'
     6: from /Users/danielmiller/.rbenv/versions/2.7.0/lib/ruby/gems/2.7.0/gems/ruby2d-0.10.0/lib/ruby2d/window.rb:563:in `update_callback'
     5: from tetris.rb:28:in `block in <main>'
     4: from /Users/danielmiller/code/2021-computer-adventures/game.rb:44:in `draw'
     3: from /Users/danielmiller/code/2021-computer-adventures/game.rb:44:in `each'
     2: from /Users/danielmiller/code/2021-computer-adventures/game.rb:45:in `block in draw'
     1: from /Users/danielmiller/code/2021-computer-adventures/game.rb:45:in `each'
/Users/danielmiller/code/2021-computer-adventures/game.rb:47:in `block (2 levels) in draw': undefined method `remove' for nil:NilClass (NoMethodError)