Devise NoMethodError 'for' ParameterSanitizer : <p>I'm going nuts with an error I'm getting every time I try to sing in/sing up on my web.</p>

<p>Heroku logs:</p>

<pre><code>Started GET "/users/sign_in" for 201.235.89.150 at 2016-07-06 01:35:03 +0000
 Completed 500 Internal Server Error in 3ms (ActiveRecord: 0.0ms)
NoMethodError (undefined method `for' for #&lt;Devise::ParameterSanitizer:0x007f5968e0a920&gt;):
 app/controllers/application_controller.rb:11:in `configure_permitted_parameters'
</code></pre>

<p>application_controller.rb</p>

<pre><code>class ApplicationController &lt; ActionController::Base
  # Prevent CSRF attacks by raising an exception.
  # For APIs, you may want to use :null_session instead.
  protect_from_forgery with: :exception

  before_filter :configure_permitted_parameters, if: :devise_controller?

    protected

        def configure_permitted_parameters
            devise_parameter_sanitizer.for(:sign_up) { |u| u.permit(:username, :email, :password, :provider, :uid) }
            devise_parameter_sanitizer.for(:account_update) { |u| u.permit(:username, :email, :password, :current_password) }
        end
end
</code></pre>

<p>The thing is it is working fine locally. It´s just on Heroku. And also it was working just fine a couple of days ago.</p>
