doc(forgejo): added some instructions for local run and development

docs/technical-documentation/product/components/forgejo/index.md

@@ -27,3 +27,51 @@ Koordination:
 * In dieser zeit arbeitet Julius an der UX-Architekturkonzeption 
 * Michael arbeitet sich ein, Technologie-Stack verstehen
 * 'Zum laufen bekommen': Lokales Aufsetzen als Nächstes gemeinsam -> Termin stellt Stephan ein
+
+## Local Development
+
+### method 1: docker compose with forgejo:latest
+
+Method 1: run a latest forgejo with sqlite - configuration is done on first login
+
+* https://forgejo.org/docs/latest/admin/installation-docker/
+
+```bash
+docker compose up -d
+
+# open localhost:3000
+
+# check registry
+
+docker login localhost:3000
+
+docker image push localhost:3000/<user>/<image>
+```
+
+### method 2: install and develop it from source
+
+* https://codeberg.org/forgejo/forgejo.git 
+
+```bash
+git clone https://codeberg.org/forgejo/forgejo.git 
+
+# enter devcontainer in VSC (takes 10 mins for the first time)
+
+# make build
+
+# then run ./gitea (sic!) --help
+# also see ./gitea forgejo-cli actions
+```
+
+### method 3: 'setup forgejo' (with runner)
+
+* https://code.forgejo.org/actions/setup-forgejo
+
+Additional links:
+* https://brainsteam.co.uk/2024/03/17/moving-from-gitea-to-forgejo-including-actions-with-docker-compose/
+* https://code.forgejo.org/forgejo/runner
+* https://linus.dev/posts/setting-up-a-self-hosted-forgejo-actions-runner-with-docker-compose/
+
+```bash
+git clone https://code.forgejo.org/actions/setup-forgejo.git
+```