initialized a knobs module

knob.py

@@ -0,0 +1,13 @@
+import pygame
+
+class Knob:
+    
+    def __init__(self, screen):
+        self.screen = screen
+        self.radius = screen.get_width()/20
+        self.fill_color = (255,0,255)
+        self.position = (screen.get_width()/2, screen.get_height()/2)
+
+    def display(self):
+        pygame.draw.circle(self.screen, self.fill_color , self.position, self.radius)
+