Added build support to Dockerfile, and include Hash in versions

@lkolbly Looks awesome!

For some reason, it's not accurately reporting though... and you're right, that API is **poorly** documented!

```
donovan@charon:~/p/jason/www$ git log test.html
commit ef38b0142fb8901927eb1ff3b0ef51264ee9eb91
Author: Jason Kolbly <jason@rscheme.org>
Date:   Wed Dec 10 02:10:54 2014 +0000

    Added a paragraph

commit 1c3e9a3f8e236676f9ecbed655b055a6cae48831
Author: Jason Kolbly <jason@rscheme.org>
Date:   Tue Dec 9 15:03:11 2014 +0000

    A new version!

commit aa812ea68b33cb3d12d4bf2b80f0ff9e0262533f
Author: Jason Kolbly <jason@rscheme.org>
Date:   Tue Dec 9 08:59:18 2014 -0600

    Initial checkin
```

vs:

```
donovan@charon:~/p/jason/www$ curl -s --digest -u [...] http://localhost:8302/edit/v/test.html |jq .
{
  "content": "<h1>Title</h1>\r\nThat was a title;\r\nthis is some body text \r\n<p>\r\n    What do you think?\r\n</p>",
  "listing": [
    {
      "comment": "A new version!\n",
      "modified": "2014-12-09T15:03:11Z",
      "hash": "1c3e9a3f8e236676f9ecbed655b055a6cae48831"
    },
    {
      "comment": "Added top level file\n",
      "modified": "2014-12-09T09:02:03-06:00",
      "hash": "86964e78d122673c52f30c1965eb271ca957aafe"
    }
  ]
}
```