How would I set up this functionality?

I want to have a text field on a photo show view with autocomplete suggesting users. When someone selects a user from the suggestion list, the photo is posted to the selected user's profile.

I understand how to set up autocomplete, but how should I structure the display of the images onto the selected user's开发者_运维技巧 profile? Would this require a new model? Perhaps polymorphic if I want it to let users do this with multiple resources?

Can a photo be posted to multiple users' profiles? If so, then I would use the "has_many through" functionality that Rails offers for many-to-many relationships.

class User < ActiveRecord::Base
  has_many :posted_photos
  has_many :photos, :through => :posted_photos
end

class Photo < ActiveRecord::Base
  has_many :posted_photos
  has_many :users, :through => :posted_photos
end

class PostedPhoto < ActiveRecord::Base
  has_many :users
  has_many :photos
end

So you end up with a table of users, a table of photos and a table which joins the two.

See this blog post for a good explanation of Rails associations.