Fix dev user seed: multiple ID was used twice.
Use blob local instead of instance.
Disable / hide MR edit blob button if cannot edit.
Add tests for tree edit routes

Critical because of possible confusion between /:id/preview
and /:id for a path that ends in preview.
Add Markdown preview to more forms

Enable Markdown previews when creating and editing issues, merge
requests, and milestones, and when editing notes.
Use GET instead of POST for Markdown previews
Refactor Markdown preview tests

Create a new shared module for common issue/merge request behavior,
use `expect` syntax instead of `should`, and avoid `visible: false` in
the `have_css` matcher.
Fix Markdown preview tests

Update Spinach tests for Markdown previews for the new-ish tab UI that
replaced the old preview/edit toggle button.
Add new Markdown preview test

Add a test to make sure that Markdown previews are available when
editing an existing issue.
Fix long line in view
Fix houndci warnings
Fix more Markdown preview tests
Fix test assertions

Make sure we're asserting the correct thing when testing visible and
invisible DOM elements.
Remove unused has_gitlab_shell3? method
add missing password prompt to mysqldump
remove extra upgrade details, add missing config

Update 7.5 update guide:

* Remove unnecessary upgrade details (they were completed in 7.4 upgrade and only needed one time)
* Add missing Nginx config details
update order of upgrade guide

GitLab needs to be stopped when backup is took.
add details on backing up your SSH host keys

Users need to backup SSH host keys if they want to do a complete restore
to the same domain and not have users get the `WARNING: REMOTE HOST
IDENTIFICATION HAS CHANGED!` message.
Make docker image file user agnostic, to prevent confusion over official images.
Make the docker commands so that people can build their own images.