Extend SteerCMS

[Philipp Schächtele]

Hey,
I'm watching the development of steercms for more than a half year now
and I'm still quite fascinated, because I'd been looking for a
extendable cms beeing based on a php-framework for a while and
steercms had been the most interesting example so far. I'm still
working on my symfony-skills and already had a look into the code of
steercms to get a impression how extendable the cms could be. Since
the documentation is still short I hope I get answers to some of my
questions here.

I want to extend symfony for my own needs and need some features which
are not implemented in steercms yet and will probably never be
implemented, namely:
- Remote Installation and Control over numerous installations of
steercms via ftp and/or a web-service (which has nothing to do with
functionability of the cms itself and which I think I could solve
already)
- A Plugin which allows the management, storage and integration into
cms-pages of media via a Media-SOAP-WebService (like Amazon S3)
- A Plugin which allows the user to add pre-defined pages or
collection of pages in a folder to his/her navigation, for example
Templates for Disclaimer, Contact-Page, but also topic-related
information pages for clients
- Plugins for interactive content pages like bulletin boards, image
gallerys, ... in general which need some management in the backend,
but also extend the frontend of the cms

But how do I actually extend SteerCMS? To be a little more precise:
Is it possible, to add own core nodes, different to the existing six
types, like a BulletinBoard or a Gallery Folder, which can be filled
with images? I was searching in the code and got the impression that
the navigation-elements supported so far are "hard coded" and probably
not that easy to extend. Would you say, that it's nearly impossible to
extend the supported content types by a plugin or a other "soft" way
(which does not require to edit core files of steer cms) or is there a
way, you could give me a sketchy desciption or at least a few hints?

How would you build up a typical plugin in steercms at all? For
example a an easy Board where the back-user can setup topics (either
in the navigation or in a seperate managament view), frontend-users
can post messages and the backend-user can moderate this messages in
the backend. If I simply extend the schema.yml, does steercms supply
own generators or a the symfony generators useable to generate an
admin-tool?

Some more documentation or even a little tutorial about writing
plugins in general would be cool and could help the project to receive
more support, at least by people writing plugins for steercms. But I'd
already be happy to get answers to my questions how to extend the
navigation and how to scaffold easy schema-extensions :)

Thanks for your help, I'll try to pay back with some plugins ;)

Cheers, Philipp