[gobject-introspection] Add a few notes to HACKING

[Johan Dahlin <johan src gnome org>]

commit 5e09002fa248adb904d9dc8ff90b1e0d51279d6a
Author: Johan Dahlin <johan gnome org>
Date:   Mon Sep 13 12:54:02 2010 -0300

    Add a few notes to HACKING

 HACKING |    7 +++++++
 1 files changed, 7 insertions(+), 0 deletions(-)
---
diff --git a/HACKING b/HACKING
index 11a9275..0c2ea14 100644
--- a/HACKING
+++ b/HACKING
@@ -1,2 +1,9 @@
+Notes to developers hacking on GObjectIntrospection
+
 * You can use the GI_SCANNER_DEBUG environment variable; see utils.py
   for a list of debug flags.
+
+* If you add a new warning, you should add a new test for it
+  in test/warn
+
+* Before pushing code to the repository, make sure to run make check