Initial docker image

Initial Docker image with:

• Dep is a dependency management tool for Go. It requires Go 1.9 or newer to compile.
• Gometalinter is concurrently run Go lint tools and normalise their output.
• Goconvey a yummy Go testing tool for gophers. Works with go test. Use it in the terminal or browser according to your viewing pleasure.
• Overalls runs test coverage tests on all packages in each directory and finally concatenates into a single file for tools like goveralls and codecov.io.
• Goimports Command goimports updates your Go import lines, adding missing ones and removing unreferenced ones.