Add the Headway project to Maps/GPS (#3035)

README.md

@@ -1141,6 +1141,7 @@ _See also: [awesome-openstreetmap](https://github.com/osmlab/awesome-openstreetm
 - [GraphHopper](https://graphhopper.com/) - Fast routing library and server using OpenStreetMap. ([Source Code](https://github.com/graphhopper/graphhopper)) `Apache-2.0` `Java`
 - [H3 Viewer](https://github.com/clupasq/h3-viewer) - View/search Uber H3 (Hexagonal Hierarchical Spatial Index) cells on a map. ([Demo](https://wolf-h3-viewer.glitch.me/)) `Apache-2.0` `HTML5`
 - [Hauk](https://github.com/bilde2910/Hauk) - Easy to setup location sharing platform that lets you temporarily share your location with anyone in real-time. ([Demo](https://github.com/bilde2910/Hauk#demo-server)) `Apache-2.0` `PHP`
+- [Headway](https://github.com/headwaymaps/headway) - Self-hostable web maps stack, powered by OpenStreetMap. Easy to set up for cities and small regions and supports full-planet maps. ([Demo](https://maps.earth/)) `Apache-2.0` `Docker`
 - [MapBBCodeShare](https://github.com/MapBBCode/share.mapbbcode.org) - Tool for sharing custom OSM maps. Support for annotated markers, polygons, lines, multi-format import/export, multiple layers, shortlinks. ([Demo](http://share.mapbbcode.org/)) `WTFPL` `PHP`
 - [Nominatim](https://nominatim.org/) - Server application for reverse geocoding (address -> coordinates) on OpenStreetMap data. ([Source Code](https://github.com/osm-search/Nominatim)) `GPL-2.0` `C`
 - [Open Source Routing Machine (OSRM)](http://project-osrm.org/) - High performance routing engine designed to run on OpenStreetMap data and offering an HTTP API, C++ library interface, and Nodejs wrapper. ([Demo](https://map.project-osrm.org/), [Source Code](https://github.com/Project-OSRM/osrm-backend)) `BSD-2-Clause` `C++`