README: Adds minimal, basic content [minor]

README.md

@@ -7,7 +7,20 @@ SPDX-License-Identifier: CC0-1.0
 # OHO to GitLab - OSH project format converter
 
 [![REUSE status](
-    https://api.reuse.software/badge/gitlab.opensourceecology.de/verein/projekte/dokumentation-bekanntmachung-von-open-hardware-regenerativer-energie-projekte/oho2gitlab)](
-    https://api.reuse.software/info/gitlab.opensourceecology.de/verein/projekte/dokumentation-bekanntmachung-von-open-hardware-regenerativer-energie-projekte/oho2gitlab)
+    https://api.reuse.software/badge/gitlab.opensourceecology.de/verein/projekte/oho-cab/oho2gitlab)](
+    https://api.reuse.software/info/gitlab.opensourceecology.de/verein/projekte/oho-cab/oho2gitlab)
 
-TODO
+This repo contains code that fetches projects from the [Open Hardware Observatory](
+https://oho.wiki/) (OHO) -
+which is a MediaWiki based DIY Hardware projects hosting/indexing website -
+and converts them to git repos,
+which then get uploaded to the [OHO OSEG GitLab Group](
+https://gitlab.opensourceecology.de/verein/projekte/oho-cab).
+
+## How to use
+
+See output of:
+
+```bash
+run/crawl -h
+```