Add .dropboxignore directory to exclude folders without using selective sync

I actively use dropbox to manage all my client projects. In addition to sorting all my client/project assets, each one has at least two github repository nested within. I did this because its an amazing user experience to have all my files, environment variables, and graphic assets sync seamlessly between 6 different workstations. The single bane of my existence is the node_modules folder. Any time I create a new project or start adding more dependencies to an exciting one - dropbox takes an eternity to sync do to this folder. Having to manually deselect every singe node_modules folder just isn't a sustainable approach. I think Dropbox could benefit from creating a .gitignore equivalent so I can remove certain folders or file types globally from the system.