Update the default method when rendering a 404

This was a very strange bug. We found that users visiting `events/introduction-to-git-1/invitation/hello@codebar.io` (we don't know how this url was generated) caused the application to crash. We fixed it with 6c83d92, but it bothered me that the 404 page was not our standard one.

It turns out that rails interprets a dot as a format separator. That meant the url was being parsed as `events/introduction-to-git-1/invitation/hello@codebar.`, with a format of 'io'. In our previous application_controller.rb file, that was caught by the line `     format.all  { head :not_found }`.

The result of this should be a nice splash page whenever there's a 404, including where a URL is malformed.

Signed-off-by: jonathan.kerr <3410350+jonodrew@users.noreply.github.com>

Author: jonodrew

app/controllers/application_controller.rb

@@ -30,10 +30,7 @@ class ApplicationController < ActionController::Base
   before_action :accept_terms, if: :logged_in?
 
   def render_not_found
-    respond_to do |format|
-      format.html { render template: 'errors/not_found', layout: false, status: :not_found }
-      format.all  { head :not_found }
-    end
+    render template: 'errors/not_found', layout: false, status: :not_found
   end
 
   protected

app/controllers/invitations_controller.rb

@@ -87,8 +87,7 @@ def cancel_meeting
   private
 
   def set_invitation
-    @invitation = Invitation.find_by(token: params[:token])
-    raise ActionController::RoutingError, 'Invitation not found' unless @invitation
+    @invitation = Invitation.find_by!(token: params[:token])
   end
 
   def load_invitation