Rocket: Use fairings for routes of sub-files

Instead of adding all routes manually in the Launch function for Rocket,
implement fairings for all the different files that adds the routing to
the rocket in a self-contained manner.

src/truth.rs

@@ -5,6 +5,7 @@ use rocket::response::Redirect;
 use rocket_db_pools::{sqlx, Connection};
 
 use pulldown_cmark::{Parser, Options};
+use rocket::fairing::AdHoc;
 use sqlx::Row;
 use crate::{auth, database, week};
 
@@ -110,3 +111,9 @@ pub async fn create_truth(week: u8, form: Form<TruthUpdateForm>,
 
     Redirect::to(uri!(week::week(week)))
 }
+
+pub fn stage() -> AdHoc {
+    AdHoc::on_ignite("Truth stage", |rocket| async {
+        rocket.mount("/", routes![create_truth, edit_truth])
+    })
+}