io: i really ought to be working on the ppu and apu by now

Signed-off-by: Amneesh Singh <natto@weirdnatto.in>

include/bus.hh

@@ -1,6 +1,7 @@
 #pragma once
 
 #include "memory.hh"
+#include "io/io.hh"
 #include <memory>
 
 namespace matar {
@@ -18,6 +19,7 @@ class Bus {
     void write_word(uint32_t address, uint32_t word);
 
   private:
+    IoDevices io;
     std::shared_ptr<Memory> memory;
 };
 }