Release a new Docker image

[monoidal]

Now that the issue with map Just (in #380) was fixed.

[aspiwack]

I failed tonight as stack gave me the following error message (which I don't really know how to handle at the moment):

Writing implicit global project config file to: /root/.stack/global-project/stack.yaml
Note: You can change the snapshot via the resolver field there.
Using latest snapshot resolver: lts-14.1
Downloading lts-14.1 build plan ...
RedownloadInvalidResponse Request {
  host                 = "raw.githubusercontent.com"
  port                 = 443
  secure               = True
  requestHeaders       = []
  path                 = "/fpco/lts-haskell/master//lts-14.1.yaml"
  queryString          = ""
  method               = "GET"
  proxy                = Nothing
  rawBody              = False
  redirectCount        = 10
  responseTimeout      = ResponseTimeoutDefault
  requestVersion       = HTTP/1.1
}
 "/root/.stack/build-plan/lts-14.1.yaml" (Response {responseStatus = Status {statusCode = 404, statusMessage = "Not Found"}, responseVersion = HTTP/1.1, responseHeaders = [("Content-Security-Policy","default-src 'none'; style-src 'unsafe-inline'; sandbox"),("Strict-Transport-Security","max-age=31536000"),("X-Content-Type-Options","nosniff"),("X-Frame-Options","deny"),("X-XSS-Protection","1; mode=block"),("X-GitHub-Request-Id","9E8A:497C:A026A:D9422:5D56DD08"),("Content-Length","15"),("Accept-Ranges","bytes"),("Date","Fri, 16 Aug 2019 16:42:50 GMT"),("Via","1.1 varnish"),("Connection","keep-alive"),("X-Served-By","cache-cdg20762-CDG"),("X-Cache","MISS"),("X-Cache-Hits","0"),("X-Timer","S1565973770.210279,VS0,VE196"),("Vary","Authorization,Accept-Encoding"),("Access-Control-Allow-Origin","*"),("X-Fastly-Request-ID","8363b8322f2148b99d080cadc1a4f41de10af490"),("Expires","Fri, 16 Aug 2019 16:47:50 GMT"),("Source-Age","0")], responseBody = (), responseCookieJar = CJ {expose = []}, responseClose' = ResponseClose})

[b-mehta]

If possible, could the new image include haddock as well?

[aspiwack]

I never managed to make a docker image since that time. We had replaced it by a nix expression contributed by @facundominguez . Now that the linear types branch has been merged in GHC, this is not really relevant anymore.