Merge pull request #120 from humanmade/backport-119-to-v3-branch

[Backport v3-branch] Add documentation for config escape hatch

other-docs/getting-started/configuration.md

@@ -135,6 +135,13 @@ if ( Altis\get_environment_type() === 'local' ) {
 }
 ```
 
+### Early Loading Escape Hatch
+
+Altis will also load a file located at `.config/load-early.php` as soon as possible in the loading process. This file is loaded before the plugin API (`add_action`/`apply_filters`), and before Composer autoloads.
+
+This should **only** be used as an escape hatch where absolutely necessary, as configuration should be set in the above files wherever possible.
+
+If you need to use `load-early.php`, consider filing a feature request for an Altis configuration option.
 
 ## Next Steps