Add docs to Kemal::OverrideMethodHandler

src/kemal/override_method_handler.cr

@@ -1,4 +1,13 @@
 module Kemal
+  # Adds support for `_method` magic parameter to simulate PUT, PATCH, DELETE requests in an html form.
+  #
+  # This middleware is **not** in the default Kemal handlers. You need to explicitly add this to your handlers:
+  #
+  # ```ruby
+  # add_handler Kemal::OverrideMethodHandler
+  # ```
+  #
+  # **Important:** This middleware consumes `params.body` to read the `_method` magic parameter.
   class OverrideMethodHandler
     include HTTP::Handler
     INSTANCE = new
@@ -10,14 +19,14 @@ module Kemal
     def call(context)
       request = context.request
       if request.method == OVERRIDE_METHOD
-        if context.params.body.has_key?(OVERRIDE_METHOD_PARAM_KEY) && override_method_valid?(context.params.body["_method"])
+        if context.params.body.has_key?(OVERRIDE_METHOD_PARAM_KEY) && override_method_valid?(context.params.body[OVERRIDE_METHOD_PARAM_KEY])
           request.method = context.params.body["_method"].upcase
         end
       end
       call_next(context)
     end
 
-    def override_method_valid?(override_method : String)
+    private def override_method_valid?(override_method : String)
       ALLOWED_METHODS.includes?(override_method.upcase)
     end
   end