User info on profile

https://trello.com/c/G5ZpuB4N/47-user-info-on-user-show-page

![image](https://cloud.githubusercontent.com/assets/8669803/5114170/5627a3fc-7004-11e4-920e-c1d4547b7471.png)
Could you have `user_image` helper incorporate all of this?

``` erb
<%= user_image @user %>
```

``` ruby
# in app/helpers/application_helper.rb
...
def user_image(user)
  image_tag, image_or_default(user), class: "profile-image"
end

def image_or_default(user)
  user.avatar_url.presence || DEFAULT_IMAGE_URL
end
```