Add docs on how to turn off SSL verification on GH oauth

In https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/323/ we added support
to disable SSL verification because attempting to import projects from a
self-signed GH Enterprise instance will fail with an SSL error.

doc/integration/github.md

@@ -103,12 +103,54 @@ GitHub will generate an application ID and secret key for you to use.
 1.  Save the configuration file.
-1.  [Reconfigure][] or [restart GitLab][] for the changes to take effect if you
+1.  [Reconfigure GitLab][] or [restart GitLab][] for the changes to take effect if you
     installed GitLab via Omnibus or from source respectively.
 On the sign in page there should now be a GitHub icon below the regular sign in form.
 Click the icon to begin the authentication process. GitHub will ask the user to sign in and authorize the GitLab application.
 If everything goes well the user will be returned to GitLab and will be signed in.
-[reconfigure]: ../administration/restart_gitlab.md#omnibus-gitlab-reconfigure
+### GitHub Enterprise with Self-Signed Certificate
+
+If you are attempting to import projects from GitHub Enterprise with a self-signed
+certificate and the imports are failing, you will need to disable SSL verification.
+It should be disabled by adding `verify_ssl` to `false` to the provider configuration.
+
+For omnibus package:
+
+```ruby
+  gitlab_rails['omniauth_providers'] = [
+    {
+      "name" => "github",
+      "app_id" => "YOUR_APP_ID",
+      "app_secret" => "YOUR_APP_SECRET",
+      "url" => "https://github.com/",
+      "verify_ssl" => false,
+      "args" => { "scope" => "user:email" }
+    }
+  ]
+```
+
+For installation from source:
+
+```
+  - { name: 'github', app_id: 'YOUR_APP_ID',
+    app_secret: 'YOUR_APP_SECRET',
+    url: "https://github.example.com/",
+    verify_ssl: false,
+    args: { scope: 'user:email' } }
+```
+
+
+For the changes to take effect, [reconfigure Gitlab] if you installed
+via Omnibus, or [restart GitLab] if you installed from source.
+
+You will also need to disable Git SSL verification on the server hosting GitLab with the following command:
+
+```
+$ git config --global http.sslVerify false
+```
+[reconfigure GitLab]: ../administration/restart_gitlab.md#omnibus-gitlab-reconfigure
 [restart GitLab]: ../administration/restart_gitlab.md#installations-from-source
+
+