Validating a form with a foreign key

Rails
1

Hi there.
I have a problem with validating a form, where is foreign key present.
I have a table like this:
id
name
password
status_id

This is the way that status_id is implemented to the users table.

<%= select_tag (‘status_id’, options_for_select([[’-- choose one
–’, nil]] + @status.collect { |stat| [stat.status, stat.id]},
@user.status_id))%>

When I dont enter anything to any of the fields, I get an error:
NoMethodError in Users#create
Showing users/_form.rhtml where line #12 raised:
You have a nil object when you didn’t expect it! You might have expected
an instance of Array. The error occurred while evaluating nil.collect
Extracted source (around line #12):
12: <%= select_tag (‘status_id’, options_for_select([[’-- choose one
–’, ‘’]] + @status.collect { |stat| [stat.status, stat.id]},
@user.status_id))%>

And when everything is “not blank” just the status_id is nto chosen, I
get another error:
ActiveRecord::RecordNotFound in UsersController#create
Couldn’t find Status with ID=

Here is the code of my controller:
class UsersController < ApplicationController
def index
@user = User.find(:all)
end
#***************************************************************** NEW
def new
@user = User.new
@status = Status.find(:all)
end

def create
@user = User.new(params[:user])

status = Status.find(params[:status_id])
@user.status = status

if @user.save
  flash[:notice] = 'New item successfully created!'
  redirect_to(:action => 'index')
else
  flash[:notice] = 'Creating an item failed!'
  render(:action => 'new')
end

end
end

Can you suggest a solution???