feat(build): add Docker-based Debian package build system

Introduce a Docker-based build system for Debian packages to streamline
the build process and ensure consistency across environments. This
change mitigates potential build failures due to environment
discrepancies and simplifies the setup for new developers.

- Extend .gitignore to exclude debhelper and build artifacts
- Add build.sh script to automate Docker-based package building
- Update debian/control to include libyaml-dev as a build dependency
- Create debian/files to track generated Debian packages
- Add Dockerfile to define the build environment with necessary
  dependencies

Signed-off-by: Glenn Y. Rolland <glenux@glenux.net>

.gitignore

@@ -7,3 +7,7 @@
 .vagrant
 bin
 lib
+debian/.debhelper/
+debian/debhelper-build-stamp
+debian/mfm
+debian/mfm.substvars

build.sh

@@ -0,0 +1,19 @@
+#!/bin/sh
+
+# References:
+# - https://www.debian.org/doc/manuals/maint-guide/build.en.html for base principles
+# - https://www.patreon.com/posts/building-debian-23177439 for debuild output dir
+#
+set -ue
+
+mkdir -p _build || true
+
+docker build -t debbuilder --file docker/Dockerfile . 
+docker run -it -v "$(pwd):/app" -v "$(pwd)/_build:/_build" debbuilder \
+	sh -c "ARTIFACTS_DIR=/app/_build debuild --preserve-envvar=ARTIFACTS_DIR -us -uc --buildinfo-option=-u/app/_build --changes-option=-u/app/_build" \
+	|| docker run -it -v "$(pwd):/app" debbuilder 
+
+# dpkg-buildpackage -us -uc
+# debuild
+# git-buildpackage
+echo SUCCESS

debian/control

@@ -2,7 +2,7 @@ Source: mfm
 Section: utils
 Priority: optional
 Maintainer: Glenn Y. Rolland <glenux@glenux.net>
-Build-Depends: debhelper-compat (= 13), crystal, shards, make
+Build-Depends: debhelper-compat (= 13), crystal, shards, make, libyaml-dev
 Standards-Version: 4.6.0
 Homepage: https://code.apps.glenux.net/glenux/mfm
 Vcs-Git: https://code.apps.glenux.net/glenux/mfm.git

debian/files

@@ -0,0 +1,2 @@
+mfm-dbgsym_0.2.0_amd64.deb debug optional automatic=yes
+mfm_0.2.0_amd64.deb utils optional

docker/Dockerfile

@@ -0,0 +1,22 @@
+FROM debian:trixie
+
+RUN set -ex \
+    && sed -i \
+    	-e 's/Types: deb/Types: deb deb-src/g' \
+    	/etc/apt/sources.list.d/debian.sources \
+    && apt-get update \
+    && apt-get install -y --no-install-recommends \
+               build-essential \
+               cdbs \
+               devscripts \
+               equivs \
+               fakeroot \
+               crystal \
+               shards \
+               git-buildpackage \
+               libyaml-dev \
+               libxml2-dev \
+    && apt-get clean \
+    && rm -rf /tmp/* /var/tmp/*
+
+WORKDIR /app