diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000..92f693c
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,3 @@
+[submodule "wiki"]
+	path = wiki
+	url = https://github.com/nodef/extra-integer.wiki
diff --git a/package-lock.json b/package-lock.json
index e8d08d7..37b5fe0 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,6 +1,6 @@
 {
   "name": "extra-integer",
-  "version": "2.0.7",
+  "version": "2.0.8",
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {
diff --git a/package.json b/package.json
index 482bb9d..71867da 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "extra-integer",
-  "version": "2.0.7",
+  "version": "2.0.8",
   "description": "32-bit integer can store values from −2^31 to 2^31 − 1.",
   "main": "index.js",
   "scripts": {
diff --git a/wiki b/wiki
new file mode 160000
index 0000000..492227d
--- /dev/null
+++ b/wiki
@@ -0,0 +1 @@
+Subproject commit 492227dc6c4c75e4199b3a4d8ee2cabaabc705a9