Add Dart example.
diff --git a/examples/pubspec.yaml b/examples/pubspec.yaml
new file mode 100644
index 0000000..0c36dbd
--- /dev/null
+++ b/examples/pubspec.yaml
@@ -0,0 +1,5 @@
+name: addressbook
+description: dartlang.org example code.
+
+dependencies:
+  protobuf: