Emily's rest controller

Let's be real, it's an address book. anyways, @ndelage @dukegreene @rmw, any feedback would be appreciated. Thanks!
I prefer you didn't modify `params`. Since the keys & values in `params` are from user input, keep that pristine, so there's never any confusion over what the user sent up to the server. Instead, try this:

```ruby
post '/contacts/:contact_id/addresses' do #creates an address
  contact = Contact.find(params[:contact_id])
  contact.addresses.create(params[:address])

  redirect :"/contacts/#{contact.id}"
```