move velocity into Mass typeclass

src/Classes/Physics/Collidible.hs

@@ -12,9 +12,6 @@ class Mass c => Collidible c where
     -> ( V2 Double  -- Top left corner of AABB relative to position
        , V2 Double  -- Bottom right corner of AABB relative to position
        )
-
-  velocity :: c -> V2 Double
-
   -- | This Function is called for every collision for both colliding objects.
   collide
     -> c -- ^ Original object

src/Classes/Physics/Mass.hs

@@ -7,5 +7,8 @@ class Mass m where
   -- | The mass of the object
   mass :: m -> Double
 
+  -- | velocity of the object
+  velocity :: m -> V2 Double
+
   -- | The scaling factor for how much this object is affected by gravity.
   gravScale :: m -> Double