Passport LinkedIn OAuth

authentication with Passport for LinkedIn, as you need an authenticated user to access the API apparently.

API keys are stored in a file called 'config/keys.js' which is in the .gitignore file so they aren't pushed to :octocat: .

Let me know if you want them so I can set you up. For now the file looks like this

```
// linkedin keys
api_keys = {
	api_key: 'THE-API-KEY',
	secret_key: 'THE-SECRET-KEY'
};

module.exports = api_keys;
```

simple as that.