Update user information if needed

When a remote is displayed, if it has not been updated since at least 24 hours, newer informations are fetched.

Fixes #135

migrations/2018-09-03-170848_user_add_last_fetched_date/down.sql

@@ -0,0 +1,2 @@
+-- This file should undo anything in `up.sql`
+ALTER TABLE users DROP COLUMN last_fetched_date;

migrations/2018-09-03-170848_user_add_last_fetched_date/up.sql

@@ -0,0 +1,2 @@
+-- Your SQL goes here
+ALTER TABLE users ADD COLUMN last_fetched_date TIMESTAMP NOT NULL DEFAULT '2000-01-01 00:00:01';