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

In gitlab-ee!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

@@ -112,3 +112,28 @@ If everything goes well the user will be returned to GitLab and will be signed i
 [reconfigure]: ../administration/restart_gitlab.md#omnibus-gitlab-reconfigure
 [restart GitLab]: ../administration/restart_gitlab.md#installations-from-source
+
+### 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: false` to the provider configuration like so:
+
+    For GitHub Enterprise:
+
+    ```ruby
+      - { 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] 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
+```