Add Dockerfile to build an image with Go support

Signed-off-by: Benoit Donneaux <benoit@leastauthority.com>

docker/go/Dockerfile

@@ -0,0 +1,40 @@
+# Start from the official Go image based on Alpine
+FROM golang:1.19.3-alpine
+
+LABEL Description="Trac2Gitea migration tool"
+
+RUN apk --no-cache add gcc libc-dev make
+
+# Parameters for default user:group
+ARG uid=1000
+ARG user=appuser
+ARG gid=1000
+ARG group=appgroup
+
+# Add user and group for build and runtime
+RUN id ${user} > /dev/null 2>&1 || \
+    { addgroup -g "${gid}" "${group}" && adduser -D -h /home/${user} -s /bin/bash -G "${group}" -u "${uid}" "${user}"; }
+
+# Prepare directories
+RUN DIRS="/src /app" && \
+    mkdir -p ${DIRS} && \
+    chown -R ${user}:${group} $DIRS
+
+# Switch to non-root user
+USER ${user}
+
+# Inject the source code
+#COPY *.go go.* accessor/* importer log markdown /src/
+
+# Download deps, build the app and cleanup the source
+WORKDIR /src
+#RUN go mod download && \
+#    go mod verify
+
+#RUN go build -o /app/trac2gitea -ldflags '-extldflags "-static"' -buildvcs=false -v
+
+# Switch to app directory
+#WORKDIR /app
+
+# Run the app by default
+#CMD ./trac2gitea