Document cookie transport

Documentation/Books/Users/Foxx/Sessions/Transports/Cookie.mdpp

@@ -2,7 +2,24 @@
 
 `const cookieTransport = require('@arangodb/foxx/sessions/transports/cookie');`
 
-TODO
+The cookie transport stores session identifiers in cookies on the request and response object.
+
+**Examples**
+
+```js
+// Pass in a secure secret from the Foxx configuration
+const secret = module.context.configuration.cookieSecret;
+const sessions = sessionsMiddleware({
+  storage: module.context.collection('sessions'),
+  transport: cookieTransport({
+    name: 'FOXXSESSID',
+    ttl: 60 * 60 * 24 * 7, // one week in seconds
+    algorithm: 'sha256',
+    secret: secret
+  })
+});
+module.context.use(sessions);
+```
 
 !SECTION Creating a transport
 
@@ -18,20 +35,21 @@ Creates a [Transport][TRANSPORT] that can be used in the sessions middleware.
 
   * **name**: `string` (Default: `"sid"`)
 
-    TODO
+    The name of the cookie.
 
   * **ttl**: `number` (optional)
 
-    TODO
+    Cookie lifetime in seconds.
-
-  * **secret**: `string` (optional)
-
-    TODO
 
   * **algorithm**: `string` (optional)
 
-    TODO
+    The algorithm used to sign and verify the cookie. If no algorithm is specified, the cookie will not be signed or verified. See the [cookie method on the response object][RESPONSE].
+
+  * **secret**: `string` (optional)
+
+    Secret to use for the signed cookie. Will be ignored if no algorithm is provided.
 
 If a string is passed instead of an options object, it will be interpreted as the *name* option.
 
+[RESPONSE]: ../../Router/Response.md
 [TRANSPORT]: ./README.md