updated maintaining drupal instructions

[joshdentremont]

Purpose / why

Updated the instructions for maintaining Drupal to add note about production, and address some permission issues that can happen when running Composer commands.

What changes were made?

Added a note to explain that updating Drupal should be done on a development site, then those updates can be built into an image for production.

Updated composer instructions to run as nginx user which makes new files owned by nginx.

Added a note about settings.php permission issue which happens when Mac users build a site based on the starter site (Islandora-Devops/isle-dc#306).

Verification

Installing a new site using make starter then running the new Composer update command should allow you to update your modules and everything should be owned by nginx. Using the old command would have new files owned by root.

If you are on Mac you will get the error that settings.php can't be written to. Updating it's permissions so nginx can write to it should allow the composer update to succeed.

Interested Parties

• @Islandora/documentation
• @DonRichards

Checklist

Pull-request Reviewer

Pull-request reviewer should ensure the following:

• Does this PR link to related issues?
• Does the proposed documentation align with the Islandora Documentation Style Guide?
• Are the changes accurate, useful, free of typos, etc?

Person Merging

The person merging should ensure the following:

• Does mkdocs still build successfully? (This is indicated by TravisCI passing. To test locally, and see warnings, see How To Build Documentation.)
• If pages are renamed or removed, have all internal links to those pages been fixed?
• If pages are added, have they been linked to or placed in the menu?
• Did the PR receive at least one approval from a committer, and all issues raised have been addressed?

[ysuarez]

At today's tech call we feel this could be merged as is.