diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000000000000000000000000000000000000..f640cd1130c0c45e31bb254b053a16b659c5c5b6
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,3 @@
+[submodule "hashmap"]
+	path = hashmap
+	url = https://github.com/tidwall/hashmap.c
diff --git a/hashmap b/hashmap
new file mode 160000
index 0000000000000000000000000000000000000000..1c139923fe08f36143ecc0ba37cd674684f87f9c
--- /dev/null
+++ b/hashmap
@@ -0,0 +1 @@
+Subproject commit 1c139923fe08f36143ecc0ba37cd674684f87f9c