Added VHDL

v/vhdl.vhdl

@@ -0,0 +1,13 @@
+use std.textio.all;
+
+entity hello_world is
+end hello_world;
+
+architecture behaviour of hello_world is
+begin
+	process
+    begin
+       write (output, String'("Hello world!"));
+       wait;
+    end process;
+end behaviour;