add Dockerfile

This Dockerfile enables the build of a Docker image for the Aperture
binary.

updated to golang:1.13 base image

add entrypoint

fix EXPOSE port number

Dockerfile

@@ -0,0 +1,35 @@
+FROM golang:1.13-alpine as builder
+
+# Copy in the local repository to build from.
+COPY . /go/src/github.com/lightninglabs/aperture
+
+# Force Go to use the cgo based DNS resolver. This is required to ensure DNS
+# queries required to connect to linked containers succeed.
+ENV GODEBUG netdns=cgo
+
+# Explicitly turn on the use of modules (until this becomes the default).
+ENV GO111MODULE on
+
+# Install dependencies and install/build aperture
+RUN apk add --no-cache --update alpine-sdk \
+    git \
+    make \
+&&  cd /go/src/github.com/lightninglabs/aperture/cmd \
+&&  go install ./...
+
+# Start a new, final image to reduce size.
+FROM alpine as final
+
+# Expose aperture ports
+EXPOSE 11010
+
+# Copy the binaries and entrypoint from the builder image.
+COPY --from=builder /go/bin/aperture /bin/
+
+# Add bash.
+RUN apk add --no-cache \
+    bash \
+    ca-certificates
+
+# Specify the start command and entrypoint as the aperture daemon.
+ENTRYPOINT ["aperture"]