Add six open-ended fields to RedirectAction [MJ-531]

This feels very icky. I'm opening a pull request now to record our discussion and gather feedback.

After discussing with @JustinDennis, we found several options. Half of them are icky, but they're still options.
* Keep going like this and continually add new (ugly) fields to the model as needed
* Justin can examine the original source and we can name each field differently based on his findings
* We could use one of the [EAV](http://en.wikipedia.org/wiki/Entity%E2%80%93attribute%E2%80%93value_model) packages I found, though they are all outdated and possibly unmaintained. The two most popular have been dormant since January and March, respectively
* Roll our own poor-man's EAV using a foreign key to a table that is nothing but key:value mappings
* Other

EAV (or something like it) would be perfect - new fields would not require migrations and could be named meaningful names as they are added.