feat: add dockerfile

Signed-off-by: Mark Sagi-Kazar <mark.sagikazar@gmail.com>

Dockerfile

@@ -0,0 +1,56 @@
+FROM golang:1.15-alpine AS builder
+
+ENV GOFLAGS="-mod=readonly"
+
+RUN apk add --update --no-cache bash ca-certificates curl git gcc g++
+
+RUN mkdir -p /workspace
+WORKDIR /workspace
+
+ARG GOPROXY
+
+COPY go.mod go.sum ./
+RUN go mod download
+
+COPY . .
+
+RUN go build -ldflags "-s -w -X github.com/drakkan/sftpgo/version.commit=`git describe --always --dirty` -X github.com/drakkan/sftpgo/version.date=`date -u +%FT%TZ`" -o sftpgo
+
+
+FROM alpine:3.12
+
+RUN apk add --update --no-cache ca-certificates tzdata bash
+
+SHELL ["/bin/bash", "-c"]
+
+# set up nsswitch.conf for Go's "netgo" implementation
+# https://github.com/gliderlabs/docker-alpine/issues/367#issuecomment-424546457
+RUN test ! -e /etc/nsswitch.conf && echo 'hosts: files dns' > /etc/nsswitch.conf
+
+RUN mkdir -p /data /etc/sftpgo /srv/sftpgo/web /srv/sftpgo/backups
+
+RUN addgroup -g 1000 -S sftpgo
+RUN adduser -u 1000 -h /srv/sftpgo -s /sbin/nologin -G sftpgo -S -D -H sftpgo
+
+VOLUME ["/data", "/srv/sftpgo/backups"]
+
+# Override some configuration details
+ENV SFTPGO_CONFIG_DIR=/etc/sftpgo
+ENV SFTPGO_LOG_FILE_PATH=""
+ENV SFTPGO_HTTPD__TEMPLATES_PATH=/srv/sftpgo/web/templates
+ENV SFTPGO_HTTPD__STATIC_FILES_PATH=/srv/sftpgo/web/static
+
+# Sane defaults, but users should still be able to override this from env vars
+ENV SFTPGO_DATA_PROVIDER__USERS_BASE_DIR=/data
+ENV SFTPGO_HTTPD__BACKUPS_PATH=/srv/sftpgo/backups
+
+COPY --from=builder /workspace/sftpgo.json /etc/sftpgo/sftpgo.json
+COPY --from=builder /workspace/templates /srv/sftpgo/web/templates
+COPY --from=builder /workspace/static /srv/sftpgo/web/static
+COPY --from=builder /workspace/sftpgo /usr/local/bin/
+
+RUN chown -R sftpgo:sftpgo /data /etc/sftpgo /srv/sftpgo/web /srv/sftpgo/backups
+
+USER sftpgo
+
+CMD sftpgo serve