I'm in a search for social network development in Ruby and Diaspora* cought my attention. Though the idea is have a social network 'hosted' by many and owned by none is great, I don't quite understand if I can use it to make the social part of a custom site. And whether this custom site being unrelated to the network and using it's code only to support the site, or will it be integrated.
Last, can the design be changed? to fit this custom site.
I tried to find information on their FAQ and github docs, but nothing on these terms.
Diaspora* is a standalone social network server application and it is not designed to be a module in another application. Even though the license allows it, it would be very difficult to modify it to be a part of a larger application.
It however is very possible to just use the federation protocol that Diaspora* implements and integrate your application to the whole Diaspora* network, without using any of the original code. You only need to know how Diaspora* pods talk to each other.
If you want to implement social media functionality into an existing Ruby application, you are better off choosing some social media framework, not Diaspora*. See this question for some example projects.