Adds Dockerfile (#26)

Dockerfile

@@ -0,0 +1,28 @@
+# Use the official Golang image to create a build artifact.
+# This is based on Debian and sets the GOPATH to /go.
+# https://hub.docker.com/_/golang
+FROM golang:1.19 as builder
+
+# https://stackoverflow.com/questions/36279253/go-compiled-binary-wont-run-in-an-alpine-docker-container-on-ubuntu-host
+ENV CGO_ENABLED=0
+
+# Set the current working directory inside the container.
+WORKDIR /go/src/github.com/score-spec/score-humanitec
+
+# Copy the entire project and build it.
+COPY . .
+RUN GOOS=linux GOARCH=amd64 go build -o /usr/local/bin/score-humanitec ./cmd/score-humanitec
+
+# Use the official Alpine image for a lean production container.
+# https://hub.docker.com/_/alpine
+# https://docs.docker.com/develop/develop-images/multistage-build/#use-multi-stage-builds
+FROM alpine:3
+
+# Set the current working directory inside the container.
+WORKDIR /score-humanitec
+
+# Copy the binary from the builder image.
+COPY --from=builder /usr/local/bin/score-humanitec /usr/local/bin/score-humanitec
+
+# Run the binary.
+ENTRYPOINT ["/usr/local/bin/score-humanitec"]