Ruby Rails - How can I assign a new value to an attribute via link_to?

I have a model called projects, and it has an attribute, :opstatus, which I would like to set to 3 (opstatus is an int). I need this to happen when the user clicks the following link:

<%= link_to 'Close', projects_path, :action => :newmeth %>

For which I created the method (in the projects_controller):

def newmeth
    @project.update_attribute(:opstatus, 3)
end

But when the user clicks the link, nothing happens! The database tells me that opstatus still =s 3, and there is no error message.

Can anyone give me a clue as to what I have done wrong? Thanks!

Below is the entire contents of my routes.rb file

Rails.application.routes.draw do

get 'sheetread/show'
get 'sheetread' => 'sheetread#show'

get 'users/index'

get 'users/new'
get 'welcome/index'
get 'signup' => 'users#new'

get    'login'   => 'sessions#new'
post   'login'   => 'sessions#create'
delete 'logout'  => 'sessions#destroy'

resources :users
resources :spreadsheets


resources :projects do
    resources :comments
end

priority.

root 'welcome#index'