Struggling with relatively simple out of model updating

I’m trying to do a In/Out thing…

In my in_outs_controller.rb

def edit_in_out
@in_out = InOut.new
@in_out.user_id = params[:id]
@user = User.find_by_id(@in_out.user_id)
if @in_out.save
@user.update_attribute(:in_out, params[:user][:in_out])
flash[:notice] = ‘In/Out was successfully updated.’
redirect_to :action => ‘list’
else
render :action => ‘edit_io’
end
end

The error I get is…
ActiveRecord::AssociationTypeMismatch
InOut expected, got String

Request
Parameters: {“user”=>{“will_return”=>"", “in_out”=>“In”}, “commit”=>"
Save ", “id”=>“19”}

Users table has
add_column :users, :in_out, :string, :limit => 3
add_column :users, :will_return, :string, :limit => 48

How can I do this?

Craig