suggested changes that includes:

moving actions for custom domain in its own controller
use separate service class for custom domains
updated help text for custom domains
increased test coverage for custom domains

app/views/admin/conference_domains/show.haml

@@ -0,0 +1,86 @@
+.row
+  .col-md-12
+    %h1
+      Custom domain
+    %p.text-muted
+      Point your own domain to #{@conference.title}
+%hr
+.row
+  .col-md-12
+    %table.table
+      %thead
+        %th Domain Name
+        %th Correctly points to #{@conference.short_title}
+        %th Actions
+      %tbody
+        %tr
+          %td
+            = @conference.custom_domain
+          %td
+            - ck_domain = ConferenceDomainsService.new(conference: @conference).check_custom_domain
+            - if ck_domain == true
+              %span.glyphicon.glyphicon-ok
+            - elsif ck_domain == false
+              %span.glyphicon.glyphicon-remove
+            - else
+              %i
+                = ck_domain
+          %td
+            .btn-group
+              = link_to 'Edit', admin_conference_conference_domains_edit_path(@conference.short_title),
+                method: :get, class: 'btn btn-primary'
+              = link_to 'Delete', admin_conference_path(@conference.short_title),
+                method: :delete, class: 'btn btn-danger'
+.row
+  .col-md-9.text-right
+    = link_to '#status-help', class: 'btn btn-default',  "data-toggle"=>"collapse" do
+      Need Help?
+.row
+  .col-md-12
+    .collapse#status-help
+      %h2
+        Instructions to add your own domain
+      %hr
+      %p
+        Normally, your conference's splash page is available at:
+        %strong
+          osem.io/conferences/#{@conference.short_title}
+      %p
+        However, we also provide support for hosting conferences on your own domain.
+
+        Terms to get familiar with:
+      %p
+        %strong
+          Domain registrar:
+        Domain registrar is just another term used for providers who work on reserving domain names.
+      %p
+        %strong
+          CNAME:
+        A Canonical Name record is a resource used which defines that your domain name is an alias for another domain name.
+      %p
+        To add your own domain you can follow these
+        %i
+          three
+        steps:
+      %ol
+        %li
+          Pick a domain you want to host your conference on from a domain registrar or register it with a domain registrar.
+        %li
+          Add your own domain name to OSEM
+          = link_to 'here', admin_conference_conference_domains_edit_path(id: @conference.short_title)
+        %li
+          The last step is adding a CNAME record in your registrar’s DNS Settings.
+          Different registrars have different ways of adding a CNAME record.
+          The following guides would help you setup a CNAME record depending upon the registrar of your domain.
+          If it doesn’t, you probably should get in touch with your domain registrar and ask him how to register a CNAME record in their platform.
+          %ul
+            %li
+              = link_to 'GoDaddy', 'https://in.godaddy.com/help/add-a-cname-record-19236'
+            %li
+              = link_to 'Namecheap', 'https://www.namecheap.com/support/knowledgebase/article.aspx/9646/2237/how-can-i-set-up-a-cname-record-for-my-domain'
+            %li
+              = link_to 'BlueHost', 'https://my.bluehost.com/cgi/help/cname#creating_a_cname'
+            %li
+              = link_to '12-reg.co.uk', 'https://www.123-reg.co.uk/support/answers/Domains/Domain-Configuration/how-do-i-set-up-a-cname-record-on-my-domain-name-1198/'
+            %li
+              = link_to '1&1', 'https://help.1and1.com/domains-c36931/manage-domains-c79822/dns-c37586/enter-a-cname-for-your-subdomain-a643600.html'