add queue functionality

src/music_queue.py

@@ -0,0 +1,9 @@
+class music_queue:
+	def __init__(self):
+		self.elem = []
+	def enqueue(self, a):
+		self.elem.append(a)
+	def dequeue(self):
+		return self.elem.pop(0)
+	def has_next(self):
+		return self.elem