No route matches [GET] "/users/sign_out"

I had a similar problem, but addition of the :method=> :delete didn't work. I was able to add a new route for a the get request by commenting out the devise_for :users and adding

devise_for :users do
  get '/users/sign_out' => 'devise/sessions#destroy'
end

I had a similar problem. My view code was like this:

  <%= link_to " exit", destroy_user_session_path, method: :delete %>

After adding the following change to routes.rb it worked,

devise_for :users

devise_scope :user do  
   get '/users/sign_out' => 'devise/sessions#destroy'     
end

You can end a session via get by changing the devise configuration in initializers.

# The default HTTP method used to sign out a resource. Default is :delete.
config.sign_out_via = :get

Just open the link and your session is removed.