Merge branch 'patch-1' into 'master'

Update github.md

Hi, I ran into a few pitfalls while I enabled OmniAuth to be able to migrate repos from github to my omnibus-gitlab instance today, so here are my findings:

These docs state thate the default authorization callback URL is `'${YOUR_DOMAIN}/import/github/callback'`, but the screenshot only shows `'${YOUR_DOMAIN}'`, which works, so I removed the ambiguity.

When editing `gitlab_rails['omniauth_providers']` for github.com, you have to omit the `"url" => "https://github.com/",` part, otherwise it won't work (OmniAuth will stay deactivated). This is backed by the configuration details of the "from-source-installation" which also omits the url in the `yml` file.

After changing the `gitlab.rb` file, `sudo gitlab-ctl reconfigure` needs to be run, which is missing in the docs.

Following the updated version of this documentation I was able to enable OmniAuth.

If anything I edited is wrong, please correct me, as I don't know how the "from-source-installations" would react to my changes.

Best regards,
Florian

See merge request !4072

doc/integration/github.md

@@ -48,6 +48,21 @@ GitHub will generate an application ID and secret key for you to use.
 
     For omnibus package:
 
+    For GitHub.com:
+    
+    ```ruby
+      gitlab_rails['omniauth_providers'] = [
+        {
+          "name" => "github",
+          "app_id" => "YOUR_APP_ID",
+          "app_secret" => "YOUR_APP_SECRET",
+          "args" => { "scope" => "user:email" }
+        }
+      ]
+    ```
+    
+    For GitHub Enterprise:
+    
     ```ruby
       gitlab_rails['omniauth_providers'] = [
         {
@@ -86,7 +101,7 @@ GitHub will generate an application ID and secret key for you to use.
 
 1.  Change 'YOUR_APP_SECRET' to the client secret from the GitHub application page  from step 7.
 
-1.  Save the configuration file.
+1.  Save the configuration file and run `sudo gitlab-ctl reconfigure`.
 
 1.  Restart GitLab for the changes to take effect.