Add submodule for utf8_range
diff --git a/.gitmodules b/.gitmodules
index 7a46a17..db938cf 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -9,3 +9,6 @@
 [submodule "third_party/jsoncpp"]
 	path = third_party/jsoncpp
 	url = https://github.com/open-source-parsers/jsoncpp.git
+[submodule "third_party/utf8_range"]
+	path = third_party/utf8_range
+	url = https://github.com/protocolbuffers/utf8_range.git
diff --git a/third_party/utf8_range b/third_party/utf8_range
new file mode 160000
index 0000000..77f787e
--- /dev/null
+++ b/third_party/utf8_range
@@ -0,0 +1 @@
+Subproject commit 77f787ec84cce7c4c7059a614e3147eac23d511e