fix: add yarn gitignores to root

AndersDJohnson · AndersDJohnson · commit d6634592ab42 · 2017-02-09T00:10:54.000-06:00
diff --git a/.gitignore b/.gitignore
@@ -6,4 +6,6 @@ my-app*
 template/src/__tests__/__snapshots__/
 lerna-debug.log
 npm-debug.log
+yarn-debug.log*
+yarn-error.log*
 /.changelog
