Update wp-config.php during subsequent provisioning

[montchr]

Current Behavior

As of #11 /var/www/spiritedmedia.dev/wp-config.php will only be modified upon initial provisioning, i.e. when the install script is run for the first time and the box is created.

Upon subsequent runs of vagrant provision/vagrant up --provision, Nginx and PHP configs will be copied from synced folders to their respective locations on the box, but wp-config.php will remain untouched. That means that any necessary updates to wp-config.php will need to occur on the box directly and in config/wp-config-additions.txt.

This is because of the complexity of modifying an existing file, where we insert the contents of config/wp-config-additions.txt into a specific location within the existing wp-config.php during initial provision.

Expected Behavior

Customizations to wp-config.php should be wiped and the contents of wp-config-additions.txt should be inserted into that file again so that we can easily add important configuration changes to the additions file and run vagrant provision to bring them into effect.

A possible approach could be creating a backup of wp-config-additions.txt alongside wp-config.php, searching wp-config.php for the contents of that backup, deleting those lines, and inserting the contents of the current version of wp-config-additions.txt from the config/ synced folder.