Add one or two more demo users' posts

[nohuhu]

While working on my implementation I found that it would be helpful to see more than two users' content (Gerome + my signed-in user), e.g. while testing feed where if I follow Gerome I shouldn't see other demo user posts, etc.

It would also be helpful if that second (third?) demo user had comments on Gerome's posts, and vice versa. Content itself does not really matter, the classic Lorem Ipsum would do just fine.

Very helpful would be to have more than 10 posts visible without authentication, to test pagination in logged-out mode.