setting user alias as message recipient - ruby-on-rails

Question

I have two models, user and treating (which you can think of as a message).
User:
class User < ActiveRecord::Base
attr_accessible :name, :email, :password, :password_confirmation
has_secure_password
has_many :sent_treatings, :foreign_key => "requestor_id", :class_name => "Treating", dependent: :destroy
has_many :received_treatings, :foreign_key => "requestee_id", :class_name => "Treating", dependent: :destroy
end
Treating:
class Treating < ActiveRecord::Base
attr_accessible :intro, :proposed_date, :proposed_location
validates :intro, presence: true, length: { maximum: 190 }
validates :requestor_id, presence: true
validates :requestee_id, presence: true
belongs_to :requestor, class_name: "User"
belongs_to :requestee, class_name: "User"
default_scope order: 'treatings.created_at DESC'
end
I'm having trouble in my treatings controller setting 'requestee':
class TreatingsController < ApplicationController
before_filter :signed_in_user
def create
requestee = ?
requestor = current_user
#received_treating = requestee.received_treatings.build(params[:treating])
#received_treating.requestor = requestor
if #received_treating.save
flash[:success] = "Treating request sent!"
redirect_to users_path
else
render 'static_pages/home'
end
end
end
The question mark I tried to replace with: User.find(params[:id]), hoping that the user in the current 'users/show' view would be found, but I get this error:
Couldn't find User without an ID
I also tried User.find(params[:treating][:requestee_id]), but this didn't work either. Any ideas?
Thanks!
EDIT:
views/shared/_treating_form.html.erb (this references #received_treating in the users controller, show action):
<div class="field">
<%= f.text_area :intro, placeholder: "Write your introduction here..." %>
</div>
<%= f.submit "Send", class: "btn btn-large btn-primary" %>
EDIT: adding other user profile page:
<% provide(:title, #user.name) %>
<div class="row">
<aside class="span4">
<section>
<h1>
<%= gravatar_for #user %>
<%= #user.name %>
</h1>
</section>
<% if signed_in? %>
<section>
<%= render 'shared/treating_form' %>
</section>
<% end %>
</aside>
<div class="span8">
<% if #user.received_treatings.any? %>
<h3>Treating requests (<%= #user.received_treatings.count %> received)</h3>
<ol class="treatings">
<%= render #received_treatings %>
</ol>
<%= will_paginate #received_treatings %>
<% end %>
</div>
</div>

Answer 1

I think just adding #user.id in a hidden_field would work.
<%= f.hidden_field :requestee_id, :input_html => { :value => #user.id }
<div class="field">
<%= f.text_area :intro, placeholder: "Write your introduction here..." %>
</div>
<%= f.submit "Send", class: "btn btn-large btn-primary" %>
You could also populate the field doing
<%= form_for #user.received_treatings.build do %>
<%= f.hidden_field :requestee_id %>
....
On the controller just do
#received_treating = current_user.sent_treatings.build params[:treating]
I have some doubts if this works but I think it should help you out.