Update useragent to recognize twitterbot/facebot

This UA was pulled from our logs.

ref: https://app.fizzy.do/5986089/cards/1775

Gemfile.lock

@@ -18,7 +18,7 @@ GIT
 
 GIT
   remote: https://github.com/basecamp/useragent
-  revision: b253635dc649394c72b761f09234bfd6dc87516a
+  revision: 433ca320a42db1266c4b89df74d0abdb9a880c5e
   specs:
     useragent (0.16.11)
 

test/controllers/allow_browser_test.rb

@@ -51,4 +51,14 @@ class AllowBrowserTest < ActionDispatch::IntegrationTest
 
     assert_response :success
   end
+
+  test "Facebook/Twitter bot is allowed" do
+    sign_in_as :kevin
+
+    get cards_path, headers: {
+      "User-Agent" => "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_1) AppleWebKit/601.2.4 (KHTML, like Gecko) Version/9.0.1 Safari/601.2.4 facebookexternalhit/1.1 Facebot Twitterbot/1.0"
+    }
+
+    assert_response :success
+  end
 end