This document is written to help anyone who wants to deploy the Discourse server, hosted at DigitalOcean cloud computing platform and configured to use Mailgun as the email service. Unlike most of the online tutorials and documents that are always specific to a vendor, this document pays equal attention to details of installation and provisioning at each of the participating platforms (Discourse, Mailgun and DigitalOcean).
Note the article Global worlkflow which presents flow of actions to be taken to start and finish the complete tasks, pointing out all switches from one provider to the other - information that is likely most confusing for someone approching this task for the first time. The fact that none of these tree vendors offer domain registration and provisioning service makes the flow even more complicated. In this specific case, I picked one of my favorite providers namecheap as the domain management provider, so all examples are as concrete as possible.
The internal organization of this "web book" into chapters and subchapters pretty much follows the order of the different tasks (in time) needed to install Discourse at DigitalOcean. In order to ensure easy navigation through these tasks, the book is provided with hyperlinks at all needed places.