Creation of object which doesn't have model, while creation need to create several entries in other

In application user can enter new post which contain title, content of the post and category
of post. So creating new post will be through some simple html form with few fields. Now i don’t know where to put logic for creating new post for following reasons:

Post(or posts collection) is object which is constructed from different tables, for example.

@posts = User.joins(entries: [{storage: :vote}, :category])
             .where("votes.count > ?", 0)
             .select(                      "users.username AS username, AS storage_id,
storages.title AS title, storages.content AS content, votes.count AS votes, categories.category_name AS category_name")
             .order("votes.count DESC")

So when user create new post application must create new entries in different tables:

1.Create new entry in entries table. (id, user_id, category_id)
2. Create new entry in storages table.(id, title, content, entry_id)
3. Create new entry in vote table.(id, count, storage_id)

In situation where post is model i can use something like resources: posts then in posts controller through new and create i can create new post, but what in situation like this where i don’t need posts controller nor post model? So, question is: which place is more appropriate to put logic for creating new post? Question1

My solution is to craete Storages controller with resource: storages, :only => [:new, :create] then through new and create of this controller to populate different tables in db? I’m forcing here only
because i dont see any point of other CRUD actions here(like showing all or one storage), because i will not use storages individually but in
conjunction with other tables. So from views/storages through new.html.erb and create.html.erb i can construct new post? Question2

Another solution is to create Post controller which doesn’t have “corresponding” post model as i stated before. Here i’m guessing i can’t
use restful routes(CRUD) because there is not :id of post? I only can make manually non-restful routes like:
post 'posts/create/:title/:content/:category' => 'posts#create', :as => 'create_post' then from params[:title], params[:content] and params[:category] to populate other tables. Question3I assume that i need tableless-model for post?