Updating guide to override security

Change-Id: If774562692ff65061cfb9a2398c5033775b07b9b
diff --git a/mdl_relaxed.rb b/mdl_relaxed.rb
index 92e3fe8..bebc671 100644
--- a/mdl_relaxed.rb
+++ b/mdl_relaxed.rb
@@ -48,3 +48,6 @@
 
 # Exclude rule: Emphasis used instead of a header
 exclude_rule 'MD036'
+
+# Gitbook won't care about multiple blank lines
+exclude_rule 'MD012'