benzenwen

Results 2 issues of benzenwen

Add detail for second level children for :firebase/update, i.e. use string keys.

Firebase's [transaction](https://firebase.google.com/docs/reference/js/firebase.database.Reference#transaction) provides for atomic data modification, useful for multi-user applications that edit data dynamically. This pull requests implements a straight JavaScript translation :firebase/transaction, and a more Clojure-y variant :firebase/swap...