Redmine plugin to send Issues data to MailUP

We have a Redmine installation with several custom fields associated to issues.
When an user creates or updates an issue the data of a selection of these custom fields must update the information of our database at MailUP.

MailUP is a mass mailing platform, they already have Ruby Gems so it shouldn't be hard to integrate with them.

The fields mapping will be fixed, no need to make backend configuration. It can be an array in the plugin code, we will change it very rarely.
We will provide a mapping between Redmine issue fields name and MailUP fields ID.

On Redmine the plugin should hook on :controller_issues_edit_after_save and :controller_issues_new_after_save.

So when an issue is either created or updated:
1. the email address should be checked on MailUP if already present, to obtain Customer ID
2. if not present the user should be added using http://help.mailup.com/display/mailupapi/Recipients#Recipients-Addasinglerecipient/subscriber-synchronousimport
3. if present all the user info should be updated using http://help.mailup.com/display/mailupapi/Recipients#Recipients-Updatepersonaldatafieldsofasubscriber

We will provide MailUP developer account and Oauth2 ID/Secret.