add http method override section

HTTP-method-override.md

@@ -0,0 +1,60 @@
+The use of specific custom HTTP headers such as X-HTTP methods override can be very handy while developing and promoting a REST API. When deploying REST API based web services, you may encounter access limitations on both the **server** and **client** sides.
+
+Some Firewalls do not support PUT, DELETE or PATCH requests.
+
+-----------
+
+The [Method Override](https://github.com/kataras/iris/tree/master/middleware/methodoverride) wrapper lets you use HTTP verbs such as PUT or DELETE in places where the client doesn't support it.
+
+### Server
+
+```go
+package main
+
+import (
+    "github.com/kataras/iris/v12"
+    "github.com/kataras/iris/v12/middleware/methodoverride"
+)
+
+func main() {
+    app := iris.New() 
+
+    mo := methodoverride.New( 
+        // Defaults to nil. 
+        // 
+        methodoverride.SaveOriginalMethod("_originalMethod"), 
+        // Default values. 
+        // 
+        // methodoverride.Methods(http.MethodPost), 
+        // methodoverride.Headers("X-HTTP-Method", "X-HTTP-Method-Override", "X-Method-Override"), 
+        // methodoverride.FormField("_method"), 
+        // methodoverride.Query("_method"), 
+    ) 
+    // Register it with `WrapRouter`. 
+    app.WrapRouter(mo)
+
+    app.Post("/path", func(ctx iris.Context) {
+        ctx.WriteString("post response")
+    })
+
+    app.Delete("/path", func(ctx iris.Context) {
+        ctx.WriteString("delete response")
+    })
+
+    // [...app.Run]
+}
+```
+
+### Client
+
+```js
+fetch("/path", {
+    method: 'POST',
+    headers: {
+      "X-HTTP-Method": "DELETE"
+    },
+  })
+  .then((resp)=>{
+      // response body will be "delete response". 
+ })).catch((err)=> { console.error(err) })
+```

Home.md

@@ -21,6 +21,7 @@ This wiki is the main source of documentation for **developers** working with (o
     * [[Wrap the Router|Routing-wrap-the-router]]
     * [[Override Context|Routing-override-context]]
     * [[Context Methods|Routing-context-methods]]
+* [[HTTP Method Override]]
 * [[API Versioning]]
 * [[Content Negotiation]]
 * [[Response Recorder]]

_Sidebar.md

@@ -16,6 +16,7 @@
     * [[Wrap the Router|Routing-wrap-the-router]]
     * [[Override Context|Routing-override-context]]
     * [[Context Methods|Routing-context-methods]]
+* [[HTTP Method Override]]
 * [[API Versioning]]
 * [[Content Negotiation]]
 * [[Response Recorder]]