week: Add week number to the DisplayTruth

In order to have all the relevant information for displaying a truth everywhere, add
its week number.
Fetch it during the week rendering and use it for the link back.

src/week.rs

@@ -64,7 +64,7 @@ pub async fn week(week_number: u8, mut db: Connection<Db>, cookies: &CookieJar<'
             vote_data: vote_data
         })
     } else {
-        let truths: Vec<DisplayTruth> = match sqlx::query_as("SELECT id, number, author_id, rendered_text FROM Truths WHERE week == $1 ORDER BY number")
+        let truths: Vec<DisplayTruth> = match sqlx::query_as("SELECT id, week, number, author_id, rendered_text FROM Truths WHERE week == $1 ORDER BY number")
             .bind(week_number)
             .fetch_all(&mut **db).await {
             Ok(v) => v,