feat: out-of-box experience (#2)

Reviewed-on: https://git.reya.su/reya/signed/pulls/2

crates/workspace/src/lib.rs

@@ -0,0 +1,16 @@
+mod views;
+mod workspace;
+
+pub mod image_cache;
+
+use gpui::{App, AppContext, Entity, Window};
+use gpui_component::Root;
+pub use views::{RepoListView, SidebarPanel};
+pub use workspace::Workspace;
+
+/// Build the root view tree. Requires `signed_state::init` and
+/// `gpui_component::init` to have been called first.
+pub fn root(window: &mut Window, cx: &mut App) -> Entity<Root> {
+    let view = cx.new(|cx| Workspace::new(window, cx));
+    cx.new(|cx| Root::new(view, window, cx))
+}