Removed id function from diesel models.

It's automaticly declared upon derive identifiable,
And there's no need to overwrite it.

hammond-gtk/src/views/podcasts_view.rs

@@ -1,6 +1,7 @@
 use gtk;
 use gtk::prelude::*;
 use gdk_pixbuf::Pixbuf;
+use diesel::associations::Identifiable;
 
 use hammond_data::dbqueries;
 use hammond_data::models::Podcast;