Add to collection button needs to work

[bnlawrence]

This works correctly now, though I think we need to modify it to handle adding to existing collections and creating new collections with descriptions. We can do that when we have the manifest button working (which we should put on the collections page).

[bnlawrence]

We've done the manifest page. I'm going to close this, and deal with adding to existing new collections in a future action.