diff --git a/.gitmodules b/.gitmodules
index b491221..781c0a1 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -313,3 +313,6 @@
 [submodule "ruby-ddmetrics"]
 	path = ruby-ddmetrics
 	url = ssh://aur@aur.archlinux.org/ruby-ddmetrics.git
+[submodule "ruby-ref"]
+	path = ruby-ref
+	url = ssh://aur@aur.archlinux.org/ruby-ref.git
diff --git a/ruby-ref b/ruby-ref
new file mode 160000
index 0000000..6bd97d6
--- /dev/null
+++ b/ruby-ref
@@ -0,0 +1 @@
+Subproject commit 6bd97d633197e7e5195f6d3385fa258927490d5e