Create transformation between input message and output message.

[NicolasPA]

From
{
"user_id": "019mr8mf4r",
"name": "Pricing Page",
"timestamp": "2012-12-02T00:30:12.984Z"
}
to
{
"user_id": "019mr8mf4r",
"number_pages_viewed_the_last_7_days": 21,
"time_spent_on_site_last_7_days": 18,
"number_of_days_active_last_7 _days": 3,
"most_viewed_page_last_7_days": "Blog: better B2B customer experience"
}