Improve support for custom controller

[adzap]

At the moment if you want to use a custom controller but otherwise use the HighVoltage internal mechanics, you have to turn off routes and unset the home_page due to the way the routes files is coded:

HighVoltage.parent_engine.routes.draw do
  if HighVoltage.home_page
    get "/#{HighVoltage.home_page}", to: redirect('/')
    root to: 'high_voltage/pages#show', id: HighVoltage.home_page
  end

  if HighVoltage.routes
    get HighVoltage.route_drawer.match_attributes
  end
end

We could nest the home page routes under the if HighVoltage.routes logic, which is more what I would expect if I disabled the gem routes. I think that is a standalone improvement.

But I would also like to suggest that the home page routes and could be modified to support just using a custom routes drawer to enable full custom controller support. One way is to add a new config option controller_name or rack_endpoint with a default of "high_voltage/pages" which could be inserted in the routes i.e.

root to: "#{HighVoltage.controller_name}#show", id: HighVoltage.home_page

and a similar change in the route drawers.

Alternatively we could modify the current route drawers to use a different get options method signature
i.e. in routes drawer

def self.match_attributes
  [
    "/#{HighVoltage.content_path}*id",
    {
      :to => 'high_voltage/pages#show',
      :as => :page,
      :format => false
    }
  ]
end

paired with

HighVoltage.parent_engine.routes.draw do
  if HighVoltage.home_page
    get "/#{HighVoltage.home_page}", to: redirect('/')
    root to: HighVoltage.route_drawer.match_attributes[:to], id: HighVoltage.home_page
  end

  if HighVoltage.routes
    get(*HighVoltage.route_drawer.match_attributes)
  end
end

This is neatly internally consistent, but has the problem of backward compatibility. Which could be overcome with a little ugly check on the return value type of match_attributes being an array or hash.