Add migration file using artisan migrate commands.

Note that in laracast tutorial, the flag `--table` is no longer used
in the current version (4.2) of laravel. Instead, use the command
`php artisan migrate:make create_users_table --create=users` to create
the new table migration file properly.
Also, had to use command `php composer dump-autoload -o` to be able
to use the `migrate:rollback` command the first time.
Modify for error log file.