[ci skip]

- Rename "Finishing Up" to "Nginx configuration"
- Add fourth "Finishing Up" section
- Add Troubleshooting section with a link to backup restoration docs
- Change a few indented blocks into fenced blocks so they're highlighted
  properly.
- Added Marin's suggestions for CI-to-CE-on-different-server section.

[ci skip]

Fixes a few links and typos, and reorganizes the CI "Create a backup"
section.

We didn't specify that the db user needs the right to create
temporary tables before.
That's why the migration will fail on most installations.
This commits removes the "TEMPORARY" from the migration
and changes the documentation to include the necessary rights for the future.

I don't really like making these an ordered list since they're mutually
exclusive, but I think the structure is what's important.

[ci skip]

[ci skip]

add a test for to_hook_data of issue model

update CHANGELOG

[ci skip]

[ci skip]

The help file on Markdown that is included with Gitlab CE (7.14.3 d321305c)
and also gitlab.com (see https://gitlab.com/help/markdown/markdown#links)
contains a typo in the description of a link to a wiki page.

Hopefully this will make it a bit clearer that we're excluding a certain
database type.

[ci skip]