2 small things.
a) Show me the code to start with, don't send me digging for it. A SimpleController example as the very first thing would help give a feel for the project, and makes me more likely to consider the project.
b) If there's an easier way (like the drogon_ctl utility at the start of Quickstart [0]), show that first, and the more detailed way second.
Other than that, it looks great. I've used libmicrohttpd a few times, so a bit less of an overhead always looks great.