Routes error on [POST] [Ruby on Rails] - ruby-on-rails

Question

Right now I'm building a project management app in rails, here is some background info:
Right now i have 2 models, one is User and the other one is Client. Clients and Users have a one-to-one relationship (client -> has_one and user -> belongs_to which means that the foreign key it's in the users table)
So what I'm trying to do it's once you add a client you can actually add credentials (add an user) to that client, in order to do so all the clients are being displayed with a link next to that client's name meaning that you can actually create credentials for that client.
So in order to do that I'm using a helper the link to helper like this.
<%= link_to "Credentials",
{:controller => 'user', :action => 'new', :client_id => client.id} %>
Meaning that he url will be constructed like this:
http://localhost:3000/clients/2/user/new
By creating the user for the client with he ID of 2.
And then capturing the info into the controller like this:
#user = User.new(:client_id => params[:client_id])
EDIT: This is what i currently have in my View/Controller and Routes
I keep getting this error: No route matches "/clients//user" with {:method=>:post}
Routes
ActionController::Routing::Routes.draw do |map|
map.resources :users
map.resources :clients, :has_one => :user
map.connect ':controller/:action/:id'
map.connect ':controller/:action/:id.:format'
end
Controller
class UsersController < ApplicationController
before_filter :load_client
def new
#user = User.new
#client = Client.new
end
def load_client
#client = Client.find(params[:client_id])
end
def create
#user = User.new(params[:user])
#user.client_id = #client.id
if #user.save
flash[:notice] = "Credentials created"
render :new
else
flash[:error] = "Credentials created failed"
render :new
end
end
View
<% form_for #user, :url => client_user_url(#client) do |f| %>
<p>
<%= f.label :login, "Username" %>
<%= f.text_field :login %>
</p>
<p>
<%= f.label :password, "Password" %>
<%= f.password_field :password %>
</p>
<p>
<%= f.label :password_confirmation, "Password Confirmation" %>
<%= f.password_field :password_confirmation %>
</p>
<%= f.submit "Create", :disable_with => 'Please Wait...' %>
<% end %>

Answer 1

Your form tag is wrong, you are posting to /users without the :client_id.
Try this:
<% form_for #user, :url => {:controller => 'users', :action => 'new', :client_id => #client.id} do |f| >
Alternatively, you could use nested resources:
config/routes.rb
map.resources :clients do |clients|
clients.resources :users
end
Controller
class UsersController < ApplicationController
before_filter :load_client
def load_client
#client = Client.find(params[:client_id])
end
# Your stuff here
end
View
<% form_for [#client, #user] do |f| %>

Answer 2

I solved this by using nested attributes, by including the user model, when creating the client. And it works flawlessly.
In case any of you guys need more info here's the two screencasts that helped me come up with as solution:
http://railscasts.com/episodes/196-nested-model-form-part-1
http://railscasts.com/episodes/196-nested-model-form-part-2