Transaction for collection
<p>How can I do using transacting t, I want to make sure the row is successful remove before saving the record:</p>

<pre><code>var Roles = bookshelf.Collection.extend({
     model: Role
);

Role.where('name', '=', 'Staff').destroy();

var roles = Roles.forge([{name: 'Staff'}, {name: 'Guest'}]);

Promise.all(roles.invoke('save')).then(function(role) {
    resolve(role);
}).catch(function (err) {
    reject({"status":"error", "data": err});
});
</code></pre>