Prerelease site does not point to prerelease demo

[pablobm]

The link to "Try the demo" in the prerelease site (https://administrate-demo-prerelease.herokuapp.com/) points to the current demo, not the prerelease one.

Not sure what's a simple way to solve this right now, so leaving this here for discussion and thinking.

[nickcharlton]

This has long bugged me, it's the same when you're running locally. I regularly find myself on the production site and find myself confused.

[goosys]

@pablobm @nickcharlton
I have a feeling this area might be involved somehow.
I’ve also been a bit confused every time I click this link.

administrate/spec/example_app/app/models/doc_page.rb

Lines 71 to 85 in f215c65

	def body
	@body ||=
	begin
	renderer = Redcarpet::Render::HTML
	markdown = Redcarpet::Markdown.new(renderer, redcarpet_config)
	source_text_with_heading = <<~MARKDOWN
	# #{title}
	#{source_text}
	MARKDOWN
	markdown.render(source_text_with_heading)
	end
	end

# Last line of `body` method
markdown.render(preprocess(source_text_with_heading))

private
def preprocess(text)
  text.gsub(/^\[demo\]:.*$/, '[demo]: /admin')
end

However, since there’s another reference with the same name pointing to a different URL in another Markdown file, it might be better to rename the reference in advance.
For example, [demo] -> [demo app].