added background

main.rb

@@ -92,7 +92,16 @@ class NumFactory < Gosu::Window
         end
       end
     end # End file loading
-    
+
+    @background = Gosu.render(@game_width, @game_height) {
+      im = Gosu::Image.new('assets/images/background_square.png', {:tileable => true})
+      (@game_width / 30).to_i.times do |ww|
+        (@game_height / 30).to_i.times do |hh|
+          im.draw(ww * 30, hh * 30)
+        end
+      end
+    }
+
     @tick_time = Time.now()
     @delta_time = 0
 
@@ -183,6 +192,7 @@ class NumFactory < Gosu::Window
       [self.width, (@camera_max_x - @camera_x) * @camera_zoom].min,
       [self.height, (@camera_max_y - @camera_y) * @camera_zoom].min,
       @background_color, 0)
+    @background.draw(0, 0, 0, @camera_zoom, @camera_zoom)
     @producers.each do |producer|
       if producer.x <= @camera_max_x && producer.x >= @camera_min_x
         if producer.y <= @camera_max_y && producer.y >= @camera_min_y