Ask HN: Platform, framework or service to build a e-learning site?

Hello HN, I am trying to build an open (editable by the community) platform for disseminating music theory. What are some platforms/frameworks/services that are suitable for this? I have considered just building everything from scratch with rails but it feels a bit overkill for this. The site is going to be heavily oriented towards content with a scattering of interactive exercises. Do you have any suggestions?