Add documentation for the cors-max-age annotation

docs/annotations.md

@@ -61,6 +61,7 @@ Key:
 | `cors-allow-headers` | Specifies the Headers allowed in CORS (Access-Control-Allow-Headers) | DNT,X-CustomHeader,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Authorization | nginx
 | `cors-allow-methods` | Specifies the Methods allowed in CORS (Access-Control-Allow-Methods) | GET, PUT, POST, DELETE, PATCH, OPTIONS | nginx
 | `cors-allow-credentials` | Specifies the Access-Control-Allow-Credentials | true | nginx
+| `cors-max-age` | Specifies the Access-Control-Max-Age | 1728000 | nginx
 
 ## Miscellaneous
 

docs/user-guide/annotations.md

@@ -25,6 +25,7 @@ The following annotations are supported:
 |[nginx.ingress.kubernetes.io/cors-allow-methods](#enable-cors)|string|
 |[nginx.ingress.kubernetes.io/cors-allow-headers](#enable-cors)|string|
 |[nginx.ingress.kubernetes.io/cors-allow-credentials](#enable-cors)|true or false|
+|[nginx.ingress.kubernetes.io/cors-max-age](#enable-cors)|number|
 |[nginx.ingress.kubernetes.io/force-ssl-redirect](#server-side-https-enforcement-through-redirect)|true or false|
 |[nginx.ingress.kubernetes.io/from-to-www-redirect](#redirect-from-to-www)|true or false|
 |[nginx.ingress.kubernetes.io/limit-connections](#rate-limiting)|number|
@@ -208,6 +209,10 @@ Example: `nginx.ingress.kubernetes.io/cors-allow-origin: "https://origin-site.co
 
 Example: `nginx.ingress.kubernetes.io/cors-allow-credentials: "true"`
 
+* `nginx.ingress.kubernetes.io/cors-max-age` controls how long preflight requests can be cached.
+
+Example: `nginx.ingress.kubernetes.io/cors-max-age: 600`
+
 
 For more information please check https://enable-cors.org/server_nginx.html