Closes GH-2481 Moved RDBMS gems into groups that can be used in Bundler 'without' arguments.

Conflicts:
	Gemfile
Alias the :postgres group to :postgresql too.

Conflicts:
	Gemfile
Add missing '[' to changelog.

Conflicts:
	changelog.md
String is enough for Refinery.roots parameter.

Conflicts:
	images/spec/features/refinery/admin/images_spec.rb
	images/spec/models/refinery/image_spec.rb
	resources/spec/features/refinery/admin/resources_spec.rb
	resources/spec/models/refinery/resource_spec.rb
Randomly order specs.
Remove carriage return from NOTE to fix its display.
Shelly Cloud installation guide

Shelly Cloud guide: error correction, polishing

Shelly Cloud guide: remove br tags, fix Step 13 link

Shelly Cloud guide: replace html #, clarifications

Shelly Cloud guide: make it more neutral
Fixed some of the formatting in the Shelly Cloud guide.
Shelly Cloud guide: simplify