There are several organizations like Chattanooga.Digital out there although with different focuses and scopes of services. One I just connected with is MayFirst, which provides shared apps and web hosting services to individuals and organizations for social justice. 

For those interested in May First's software infrastructure, check out https://admin.docs.mayfirst.org/orientation/. Pretty cool! 

If you'd like to talk with their tech lead about their operations and/or stack, let me know. I'll set something up!