Merge pull request #29 from dart-lang/dart_tool

Update .gitignore to new `dart_tool` pub cache
diff --git a/.gitignore b/.gitignore
index 76b960e..3cc62a7 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,7 +1,7 @@
 .buildlog
 .DS_Store
 .idea
-.pub/
+.dart_tool/
 .project
 .settings
 build/