institutions and harvest feeds

Institutions and harvest feeds (user-entered data meant primarily for human consumption)
 - basic models, controllers, views, routes, and migrations
 - rake tasks to save and delete sample institution and harvest feed

For reference, the ER diagram is here: https://docs.google.com/a/dp.la/drawings/d/1Wmtq6x_VBjJGgwAMhT2qUHvkuQAygMLooXd0K2eOAPo/edit

You can test in your browser by following the README instructions to generate and start a dummy application, and then creating a sample institution.  Go to `http://localhost:3000/krikri/institutions`.  You should see one institution listed.  A link from that page should take you to a view with data for that institution.  From there, another link should take you to a view with data for one sample harvest feed.

Once @mb has customized the user model, we can integrate it with the institution model and possibly rethink the routes to fit with admin and general user dashboards.
This includes a bunch of routes that aren't implemented (e.g. `#create`, `#edit`, `#update`, `#destroy`, and for `harvest_feeds`, `#index`).

Are we thinking just to take a wait and see approach to which of these end up being implemented? Or do we want to put some more work into the REST interface for these resources now, and tighten up the routes to include only those we're actually using?

If the former, let's add a comment to that effect here in the routes file, so its easy to see that those methods are deliberately unimplemented.