Add option to get additional user info

[joe1chen]

Gets additional data from /v1.1/teachers/{id} or /v1.1/students/{id} if option get_user_info is set to true.

Example with devise:

config.omniauth :clever, Settings.clever.client_id, Settings.clever.client_secret, { get_user_info: true }

[jbusser]

I have exactly the same use case, I needed more info than what the /me endpoint provided. But instead of building a URL from parts, I used the links collection that comes in the JSON returned from the /me endpoint. (An example of the links collection is at https://dev.clever.com/instant-login/users)

What do you think of something like this? This approach lets the API tell us where the canonical endpoint is for the user versus building up a URL from parts.

  extra do
    {
      raw_info: me_attrs,
      canonical: canonical_attrs
    }
  end                                                                                                                                                                                                                                                                                                                            

  def me_attrs
    @me_attrs ||= access_token.get('/me').parsed
  end

  def canonical_attrs
    @canonical_attrs ||= access_token.get(canonical_endpoint).parsed
  end

  def canonical_endpoint
    me_link('canonical').fetch('uri', '/me')
  end

  def me_link(rel)
    me_attrs.fetch('links', []).detect { |link| link['rel'] == rel } || {}
  end

[cdsmith16]

Thanks @jbusser for the update! We very much recommend using links!!

[jbusser]

Could we talk about either merging this PR or closing it? I am relying on a forked version of this gem to deliver this feature, and it would be nice to be back on a maintainer-supported gem.