diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000..c6636c2
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,6 @@
+[submodule "cpp-btree"]
+	path = cpp-btree
+	url = ../cpp-btree.git
+[submodule "json11"]
+	path = json11
+	url = ../json11.git
diff --git a/cpp-btree b/cpp-btree
new file mode 160000
index 0000000..5dc1087
--- /dev/null
+++ b/cpp-btree
@@ -0,0 +1 @@
+Subproject commit 5dc108754ad40d3b1d024f9bd7cca0595ef1a1db
diff --git a/json11 b/json11
new file mode 160000
index 0000000..97f06cb
--- /dev/null
+++ b/json11
@@ -0,0 +1 @@
+Subproject commit 97f06cb20c1e136fd37d58fb40f57dd8f8a3a4a7