Add the musictube script

diff --git a/musictube b/musictube
new file mode 100755 (executable)
index 0000000..aa7ffcb
--- /dev/null
+++ b/musictube
@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+
+# Download a file from youtube using the best audio quality.
+youtube-dl -f bestaudio ${@}