* rubocop: quit being so picky

* rubocop: miscellany

* rubocop: prefer present to blank

Adopted from GitLab CE. Generate new migration with:

    rails g post_deployment_migration name_of_migration_here

By default they are run together with db:migrate. To not run them,
the env variable SKIP_POST_DEPLOYMENT_MIGRATIONS must be set

Code by Yorick Peterse <yorickpeterse@gmail.com>, see also:

https://gitlab.com/gitlab-org/gitlab-ce/commit/83c8241160ed48ab066e2c5bd58d0914a745197c

* fix RuboCop error

RuboCop doesn't work by following error.

```
$ rubocop
Error: The `Style/TrailingCommaInLiteral` cop no longer exists. Please use `Style/TrailingCommaInArrayLiteral` and/or `Style/TrailingCommaInHashLiteral` instead.
(obsolete configuration found in .rubocop.yml, please update it)
```

it comes from RuboCop 0.53.0 [\[Fix #3394\] Separate Array & Hash Literal Comma configuration by garettarrowood · Pull Request #5307 · bbatsov/rubocop](https://github.com/bbatsov/rubocop/pull/5307)

* ci(CodeClimate): specify RuboCop version 0.54

 * https://docs.codeclimate.com/docs/rubocop#section-using-rubocop-s-newer-versions
 * [RuboCop 0.55.0 is not available yet](https://github.com/codeclimate/codeclimate-rubocop/issues/121) on CodeClimate rubocop channel

* Add handling of Linked Data Signatures in payloads

* Add a way to sign JSON, fix canonicalization of signature options

* Fix signatureValue encoding, send out signed JSON when distributing

* Add missing security context

https://github.com/codeclimate/codeclimate-rubocop/blob/08f8de84ebfb39caa96391e23816877278f6441c/Gemfile.lock#L38
Code Climate is using RuboCop v0.46.0.

Change several rules to maintain compatibility.

* Update renamed rubocop configuration options

* Remove duplicate rubocop configuration, sort options

There are many spots throughout the codebase which are showing as covered by
specs in the simplecov output -- but which are not actually run, because they
are on the same line as a guard clause.

I plan on fixing some of these issues, but don't want to keep triggering this
rubocop style violation.

My preference would be that we use the PR review process to identify places
where a guard clause might be appropriate, but that we leave this cop turned off
by default.

* disable Bundler/OrderedGems

* fix rubocop Lint/UselessAssignment

* fix rubocop Style/BlockDelimiters

* fix rubocop Style/AlignHash

* fix rubocop Style/AlignParameters, Style/EachWithObject

* fix rubocop Style/SpaceInLambdaLiteral

* downgrade rubocop 0.48.1 => 0.46.0

* exclude vendor/**/* from rubocop target files

* add frozen_string_literal comment line

* fix percent literal delimited by ( and )

* fix alignment

* remove comment disabling unknown cop

application website validation, don't link to app website if website isn't set,
also comment out animated boost icon from #464 until it's consistent with non-animated version

to the API