removes user_id column from User model to use idiomatic Rails automatic IDs

spec/vulnerabilities/xss_spec.rb

@@ -10,9 +10,9 @@ feature "xss" do
   scenario "attack\nTutorial: https://github.com/OWASP/railsgoat/wiki/A3-Cross-Site-Scripting", js: true do
     login @normal_user
 
-    visit "/users/#{@normal_user.user_id}/account_settings"
-    within("#account_edit") do
-      fill_in "First name", with: "<script>$(function() { $('div input.btn').val('RailsGoat h4x0r3d') } )</script>"
+    visit "/users/#{@normal_user.id}/account_settings"
+    within('#account_edit') do
+      fill_in 'First name', :with => "<script>$(function() { $('div input.btn').val('RailsGoat h4x0r3d') } )</script>"
 
       # password gets screwed up if you don't re-submit - need to fix
       fill_in "user_password", with: @normal_user.clear_password
@@ -22,7 +22,7 @@ feature "xss" do
 
     sleep(1)
 
-    visit "/users/#{@normal_user.user_id}/account_settings"
+    visit "/users/#{@normal_user.id}/account_settings"
 
     pending if verifying_fixed?
     expect(find("#submit_button").value).to eq("RailsGoat h4x0r3d")