title: Add arguments to the end of a url in Retrofit
body: <p>So, I'm trying to make a REST request that looks like this: <code>https://api.digitalocean.com/droplets/?client_id=[client_id]&amp;api_key=[api_key]</code></p>
  
  <p>Where <code>https://api.digitalocean.com</code> is the endpoint, and <code>@GET("/droplets/")</code> would be the annotation. I would like the end bit to be added automatically, since it would be identical for any API requests I make, and it would be a hassle to add it to each request. Is there any way to do that?</p>