Tyler Haugen-Stanley

Overriding beforeDrop() results in empty trees not reporting they are empty.

1

**Do you want to request a *feature* or report a *bug*?** Report a *bug* **What is the current behavior?** Overriding the beforeDrop callback to return false will make empty tree's...

**Do you want to request a *feature* or report a *bug*?** Reporting a *bug* **Steps to reproduce** 1. Open the [connected tree example](http://angular-ui-tree.github.io/angular-ui-tree/#/connected-trees). 2. Delete item 2, 3, & 4...

Added Gemfile.lock based on what seems like best practices these days: https://github.com/rubygems/rubygems/issues/3372