Add documentation about request_body directive in Caddyfile

src/docs/markdown/caddyfile/directives/request_body.md

@@ -0,0 +1,29 @@
+---
+title: request_body (Caddyfile directive)
+---
+
+# request_body
+
+Manipulates request body.
+
+
+## Syntax
+
+```caddy-d
+request_body {
+  max_size <value>
+}
+```
+
+- **&lt;value&gt;** is the maximum size in bytes allowed for the request body. It accepts all formats supported by [go-humanize](https://github.com/dustin/go-humanize/blob/master/bytes.go).
+
+
+## Examples
+
+Limit request body s to 10 mega bytes:
+
+```caddy-d
+request_body {
+  max_size 10MB
+}
+```