[glade] CONTRIBUTING.md: added link to HACKING file so that git mirrors pick it up when an user tries to cre

[Juan Pablo Ugarte <jpu src gnome org>]

commit 7e5dfa8ccd211945e624b0fab7fe2b19fb1b9907
Author: Juan Pablo Ugarte <juanpablougarte gmail com>
Date:   Sat Feb 27 11:09:49 2016 -0300

    CONTRIBUTING.md: added link to HACKING file so that git mirrors pick it up when an user tries to create a 
pull request

 CONTRIBUTING.md |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
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diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
new file mode 120000
index 0000000..3f7568e
--- /dev/null
+++ b/CONTRIBUTING.md
@@ -0,0 +1 @@
+HACKING
\ No newline at end of file