Well at first if you could, it would be enough to maintain a fork of the branch that interests you and use that to see it.
Regarding the database, you could use atlas if you wish, it is also a free option. However, it will not work quite well due to the limitations of the service, although if it is for development and testing it could work (although I recommend using it locally for that purpose)
Had a few slight problems getting this working. It crashed my forum and my blog, which reside on separate servers. I'm running NodeBB 0.7.0-dev with a new Wordpress install.
I installed the plugin and followed the guide on how to set it up. So all was working. I posted a blog article to test the comments engine (using forum plugin), and when I clicked the button under the article to send the article to the forum, it produced an error, which said I either had to be a member of publishers group or admin to post. I was logged into NodeBB as admin, and Wordpress too.
My forum started grinding to a halt, throwing up 502 errors in the process.
My blog collapsed and is currently sitting with a "Error establishing a database connection" notice. It's still like this, and i'll repair that when I get the chance.
The strangest aspect however is that the blog DID post to the forum. 32,800 times, no less! You can see the topic here - I set up a category for the blog articles to be posted to.
I realise to get a further insight i'll have to look into the error logs which I intend to do, but can anyone help? I've since removed the blog's server from DNS so it's no longer visitable through links and the forum is back to being the homepage.