diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000..74c037f
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,3 @@
+[submodule "spec"]
+	path = spec
+	url = https://github.com/multiformats/multibase.git
diff --git a/.gxignore b/.gxignore
new file mode 100644
index 0000000..5be883f
--- /dev/null
+++ b/.gxignore
@@ -0,0 +1 @@
+/spec/
diff --git a/spec b/spec
new file mode 160000
index 0000000..f0792f7
--- /dev/null
+++ b/spec
@@ -0,0 +1 @@
+Subproject commit f0792f703031bb01251aa99fcea6a5fe945b6297