Medias embed metadata about links shared in the news
Pages represent multiple type of data (defined by attribute "type")
user - event - project - association - business - ngo - freegroup - institution

When a new user register, a Page is automaticaly created for him
A Page typed by "user" can't change his type
ScopeGeo embed the polygon for scopeGeo
its the good data format to execute geoQuery with mongoDB
do not modify nor add any attributes in this class
it would break geoQueries
User class contain only minimal informations, needed for login.
All other informations about Users are stocked in Page class
Class Country
Class Helper
Class Mailer