Added secure flag by default if rack env shows protocol/scheme is https

[amasses]

While it is possible to specify secure: true when using the middleware, its pretty difficult to set this, and I think that this should be a default, rather then a difficult opt-in.

[bleonard]

Looks good to me. Is there a use case where someone wouldn't want us to mess with this?

[amasses]

Could be where someone is running across both HTTPS and HTTP, however I think this use case is getting much smaller.

I suspect if this is the case they should be able to load the middleware themselves and specify secure: false (though the reason for this PR was because doing that was overly complicated...

[eugeneius]

While mixing HTTP and HTTPS is less common than it used to be, it seems like overreach for us to set a secure cookie whenever the current request is over HTTPS.

For Rails apps, we could default to secure cookies if config.force_ssl is true, i.e. change:
https://github.com/taskrabbit/makara/blob/560dc333f76138c09f25f1fd3afa2d3da473f6a2/lib/makara/railtie.rb#L5

To:

  app.middleware.use Makara::Middleware, secure: app.config.force_ssl

Non-Rails apps would still have to manually pass the secure option - but they already have to add the middleware manually, so it's relatively easy to configure.

[ankane]

fwiw, config.force_ssl already makes all cookies secure.

https://github.com/rails/rails/blob/3d70e9609760cb3046cf219cd49f3e9a838a0291/actionpack/lib/action_dispatch/middleware/ssl.rb#L20