//Se inserta un mensaje que pertenece al receptor
for(User receiver : receivers) {
InboxMessage inbox = new InboxMessage(receiver, message);
inbox.save();
Tag sharedTag = Tag.findOrCreateByName("shared", receiver);
for(SharedContent sharedContent : sharedContents) {
if(Content.ContentType.PHOTO == sharedContent.type) {
ContentTag contentTag = new ContentTag(sharedContent.id, Content.ContentType.PHOTO, sharedTag);