Merge pull request #52 from scinote-eln/ma_SCI_10775

Add API key documentation [SCI-10775]

source/index.html.md

@@ -150,6 +150,19 @@ iss | Text identifier of the token issuer
 exp | Token expiration time
 sub | The ID of the current authenticated user
 
+## Alternative: API Key authenticaton
+
+<aside class="notice">
+The API key authentication feature needs to be enabled on your instance to use this option.
+</aside>
+
+If your instance has the API key functionality enabled, you can generate the API key in your user profile settings in SciNote (/users/edit). To authenticate via API key, add the following header to all requests:
+
+`Api-Key: qwerty123456...`
+
+
+The API key expires after one year. You can revoke the API key at any time in your user profile settings.
+
 # Pagination
 
 SciNote API uses pagination as specified here [JSON API](http://jsonapi.org/format/#fetching-pagination)