Add user authentication.
Add user_id to tasks migration.
Associate tasks and users.
Fix broken html.
Delete the welcome erb
Redirect to tasks/all
Add complete functionality.
Display new form on index page.
Add strikethrough css.
Toggle complete and focus on main page.
Add migration for priority.
Add task priority.
Protect routes from guest users.
Add error helpers.
Add migrations and classes for tags.
Tags on tasks.
Add migration for sub tasks.
Add associations for subtasks.
Display subtasks recursively.
Define top_level_domains helper on user object.