Adding the ability to develop Gorson completely in Docker. (#19)

* Adding the ability to develop Gorson completely in Docker.

* adding a docker compose file too

* updated docker docs to show docker-compose too

* fixing typo

Dockerfile

@@ -0,0 +1,11 @@
+FROM golang:1.13.4-alpine
+
+# borrowed with gratitude from confd
+# https://github.com/kelseyhightower/confd/blob/master/Dockerfile.build.alpine?at=09f6676
+
+WORKDIR /app
+RUN apk add --no-cache bash gcc git musl-dev
+
+COPY go.mod /app/go.mod
+COPY go.sum /app/go.sum
+RUN go mod download

docker-compose.yml

@@ -0,0 +1,6 @@
+version: '3'
+services:
+  builder:
+    build: .
+    volumes:
+    - .:/app

docs/docker.md

@@ -0,0 +1,40 @@
+# Setting up Docker
+
+This repository has been built with development of `gorson` done entirely in Docker in mind. Below are the steps required to get
+this package up and running through Docker.
+
+## Build Docker image
+
+```bash
+$ docker build -t gorson .
+```
+
+or
+
+```bash
+$ docker-compose build
+```
+
+## Run tests on Docker image
+
+```bash
+$ docker run -it -v `pwd`:/app gorson ./scripts/test.sh
+```
+
+or
+
+```bash
+$ docker-compose run --rm builder ./scripts/test.sh
+```
+
+## Create releases
+
+```bash
+$ docker run -it -v `pwd`:/app gorson ./scripts/docker-release.sh
+```
+
+or
+
+```bash
+$ docker-compose run --rm builder ./scripts/docker-release.sh
+```

scripts/docker-release.sh

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+#!/usr/bin/env bash
+set -euo pipefail
+IFS=$'\n\t'
+
+# tooling logic borrowed heavily from the talented minds of confd
+# https://github.com/kelseyhightower/confd/blob/master/Makefile
+
+cd "$( dirname "${BASH_SOURCE[0]}" )/.."
+
+./scripts/clean.sh
+mkdir -p bin
+
+VERSION=`egrep -o '[0-9]+\.[0-9a-z.\-]+' ./internal/gorson/version/version.go`
+
+# We want to make sure the final builds are formatted and linted properly.
+./scripts/format.sh
+./scripts/lint.sh
+
+# for each of our target platforms we use the gorson_builder
+#   docker container to compile a binary of our application
+>&2 echo "compiling binaries for release"
+for platform in darwin linux; do \
+    binary_name="gorson-${VERSION}-${platform}-amd64"
+    >&2 echo "compiling $binary_name"
+
+    # * GOOS is the target operating system
+    # * GOARCH is the target processor architecture
+    #     (we only compile for amd64 systems)
+    #     see https://golang.org/cmd/go/#hdr-Environment_variables
+    # * CGO_ENABLED controls whether the go compiler allows us to
+    #     import C packages (we don't do this, so we set it to 0 to turn CGO off)
+    #     see https://golang.org/cmd/cgo/
+    GOOS=$platform GOARCH=amd64 CGO_ENABLED=0 go build -o bin/$binary_name
+done