FEATURE: add required user fields to invite accept form

UX: make "accept invitation" page consistent with sign up modal

test/javascripts/acceptance/invite-show-user-fields-test.js.es6

@@ -0,0 +1,44 @@
+import { acceptance } from "helpers/qunit-helpers";
+
+acceptance("Accept Invite - User Fields", {
+  site: {
+    user_fields: [{"id":34,"name":"I've read the terms of service","field_type":"confirm","required":true},
+                  {"id":35,"name":"What is your pet's name?","field_type":"text","required":true},
+                  {"id":36,"name":"What's your dad like?","field_type":"text","required":false}]
+  }
+});
+
+test("accept invite with user fields", () => {
+  visit("/invites/myvalidinvitetoken");
+  andThen(() => {
+    ok(exists(".invites-show"), "shows the accept invite page");
+    ok(exists('.user-field'), "it has at least one user field");
+    ok(exists('.invites-show .btn-primary:disabled'), 'submit is disabled');
+  });
+
+  fillIn("#new-account-name", 'John Doe');
+  fillIn("#new-account-username", 'validname');
+  fillIn("#new-account-password", 'secur3ty4Y0uAndMe');
+
+  andThen(() => {
+    ok(exists(".username-input .good"), "username is valid");
+    ok(exists('.invites-show .btn-primary:disabled'), 'submit is still disabled due to lack of user fields');
+  });
+
+  fillIn(".user-field input[type=text]:first", "Barky");
+
+  andThen(() => {
+    ok(exists('.invites-show .btn-primary:disabled'), 'submit is disabled because field is not checked');
+  });
+
+  click(".user-field input[type=checkbox]");
+  andThen(() => {
+    not(exists('.invites-show .btn-primary:disabled'), 'submit is enabled because field is checked');
+  });
+
+  click(".user-field input[type=checkbox]");
+  andThen(() => {
+    ok(exists('.invites-show .btn-primary:disabled'), 'unclicking the checkbox disables the submit');
+  });
+
+});