Bump to 0.3.1 and format/clippy

src/database/mod.rs

@@ -88,12 +88,10 @@ impl UserDao for SqliteUserDao {
     fn user_exists(&mut self, user: &str) -> bool {
         use schema::users::dsl::*;
 
-        users
+        !users
             .filter(username.eq(user))
             .load::<User>(&mut self.connection)
-            .unwrap_or_default()
-            .first()
-            .is_some()
+            .unwrap_or_default().is_empty()
     }
 }