Merge pull request #114 from alexbirkett/load_blob_fix

Update README.md

README.md

@@ -147,7 +147,7 @@ var commit = yield repo.loadAs("commit", commitHash);
 // We then read the tree using `commit.tree`.
 var tree = yield repo.loadAs("tree", commit.tree);
 // We then read the file using the entry hash in the tree.
-var file = yield repo.loadAs("blob", tree["greeting.txt"]);
+var file = yield repo.loadAs("blob", tree["greeting.txt"].hash);
 // file is now a binary buffer.
 ```