Release process

https://github.com/hoodiehq/discussion/issues/19
@gr2m @caolan @janl @zoepage @svnlto

Here is the basic setup for an automated release process. The [TravisCI deploy](https://github.com/hoodiehq/hoodie-cli/blob/master/.travis.yml#L7-L14) is already in place, so that's all for now.

All the maintainer has to do now is run `grunt release` and wait about 4 minutes for Travis to deploy to npm.
The new version is a patch release by default, but `grunt release:major`, `grunt release:minor`, `grunt release:patch`, `grunt release:build`, `grunt release:git` are supported as well. Rather than documenting this in this repository directly I think we should update the main [CONTRIBUTING.md](https://github.com/hoodiehq/hoodie.js/blob/master/CONTRIBUTING.md#releasing-a-new-version) and link to it from here.

## Changelog

The generation is working well. As one of my PRs that was committed with the new conventions is already merged it would currently look like this:

```md
<a name="0.4.9"></a>
### 0.4.9 (2014-05-14)


#### Bug Fixes

* **paths:** use native `path` methods consistently ([73880734](https://github.com/hoodiehq/hoodie-cli/commit/73880734b22ed50f13d5a6d883ee3cfd0d66acd6))
```

As this is entirely dependent on the commit message conventions it would make sense to validate them with git hooks. This would be as easy as copying [this file](https://github.com/angular/angular.js/blob/master/validate-commit-msg.js) from the angular repo, but we have to make sure everyone does this.

So here is my idea. There is one thing probably all hoodie contributors/maintainers have in common – the hoodie-cli is already installed on their machine. We could add a command that simply installs the hooks (and prints contribution instructions). Something like `hoodie contribute`. I saw the core team is appending sponsored messages to their messages, how about `hoodie contribute --core` to streamline this process as well?