diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000..3e486cb
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,3 @@
+[submodule "ext/crlib"]
+	path = ext/crlib
+	url = https://github.com/yapb/crlib
diff --git a/ext/crlib b/ext/crlib
new file mode 160000
index 0000000..e9c1c7c
--- /dev/null
+++ b/ext/crlib
@@ -0,0 +1 @@
+Subproject commit e9c1c7c9cb290149a260c9e9c56997051be34570