add Dockerfile

Dockerfile

+FROM debian:bookworm
+
+ARG USER_UID="1000"
+ARG USER_GID=${USER_UID}
+ARG USERNAME="flutter"
+ARG WORKSPACE="/workdir"
+
+COPY --from=andrijoos/flutter:3.24.0 /flutter /opt/flutter
+
+ENV PATH=${PATH}:/opt/flutter/bin
+
+RUN apt update \
+    && apt install -y \
+    git clang cmake \
+    ninja-build pkg-config \
+    libgtk-3-dev liblzma-dev \
+    libstdc++-12-dev \
+    && groupadd --gid ${USER_GID} ${USERNAME} \
+    && useradd --uid ${USER_UID} --gid ${USER_GID} -m ${USERNAME} \
+    && mkdir -p ${WORKSPACE} \
+    && chown -R ${USERNAME}:${USERNAME} ${WORKSPACE} \
+    && chown -R ${USERNAME}:${USERNAME} /opt/flutter
+
+USER ${USERNAME}
+WORKDIR /the/workdir/path
+
+RUN dart --disable-analytics \
+    && flutter config --no-analytics \
+    && flutter precache --universal --linux
+
+# Build demo project/pipeline
+# RUN flutter create warmup --project-name warmup -t app --platforms linux
+
+# RUN cd warmup \
+#     && flutter pub get \
+#     && flutter build linux --debug