added docs for http method transformation

docs/features/configuration.rst

@@ -24,6 +24,7 @@ Here is an example ReRoute configuration, You don't need to set all of these thi
             "UpstreamHttpMethod": [
                 "Get"
             ],
+            "DownstreamHttpMethod": "".
             "AddHeadersToRequest": {},
             "AddClaimsToRequest": {},
             "RouteClaimsRequirement": {},

docs/features/methodtransformation.rst

@@ -0,0 +1,28 @@
+HTTP Method Transformation
+==========================
+
+Ocelot allows the user to change the HTTP request method that will be used when making a request to a downstream service.
+
+This achieved by setting the following ReRoute configuration:
+
+.. code-block:: json
+
+{
+    "DownstreamPathTemplate": "/{url}",
+    "UpstreamPathTemplate": "/{url}",
+    "UpstreamHttpMethod": [
+        "Get"
+    ],
+    "DownstreamHttpMethod": "POST",
+    "DownstreamScheme": "http",
+    "DownstreamHostAndPorts": [
+        {
+            "Host": "localhost",
+            "Port": 53271
+        }
+    ],
+}
+
+The key property here is DownstreamHttpMethod which is set as POST and the ReRoute will only match on GET as set by UpstreamHttpMethod.
+
+This feature can be useful when interacting with downstream apis that only support POST and you want to present some kind of RESTful interface.