[cw|frenata#5] add Dockerfile to project root

Major Changes:
* add Dockerfile for building API server image

TODO:
* add docker-compose.yml template to project root
* add build.sh script for buliding both docker images in repo
* add (possibly) a run.sh script for running both images
* add test for ensuring docker build/run works
* exec (eventually) test code in API server on container start

Dockerfile

@@ -0,0 +1,38 @@
+FROM golang:1.9-alpine as server
+
+# GOPATH = /go in the golang image
+# also $GOPATH/bin has been added to path
+
+WORKDIR /go/src/
+
+# copy API server src to be compiled
+COPY API/ ./
+
+# currently, we need to install several dependencies
+# note that we must install Docker, but when we run the container, we must
+# mount the /var/run/docker.sock of the host onto the container so the host
+# docker daemon spins up sibling containers (as opposed to Docker in Docker)
+#
+# TODO (cw|3.9.18) once we remove the dependency on gb, we will only need to
+# install docker here.
+RUN apk update && \
+    apk add --no-cache git && \
+    go get github.com/constabulary/gb/... && \
+    apk del git && \
+    apk add docker
+
+# compile and install server binary within container
+RUN gb build && \
+    mv ./bin/compilebox /go/bin
+
+FROM alpine
+
+WORKDIR /bin/
+
+# copy over single binary from build stage --^
+COPY --from=server /go/bin/compilebox .
+
+EXPOSE 6666
+
+# run comilebox API server
+CMD ["compilebox"]