bubble sort + fixed issue when writing to reference in ram.py

src/ram.py

@@ -45,7 +45,7 @@ class Ram(object):
             raise TypeError("cannot write on value")
         elif type_register == "@": # reference
             target_index = self.read_register(ref_origin, index)
-            self.write_register(ref_target, target_index, value)
+            self.write_register(value, ref_target, target_index)
 
     def op(self, type_op, r1, r2, r3):
         self.current += 1