Function get_open_and_recent_by_user 

pub async fn get_open_and_recent_by_user(
    conn: &mut PgConnection,
    user_id: Uuid,
    course_ids: &[Uuid],
    closed_limit: i64,
) -> ModelResult<Vec<AgentChangeset>>

The user’s open changesets in the courses and their closed_limit most recent closed ones, newest first.