Feature/docs (#165)

* initial readthedocs commit

* docs moved to sphinx / rst / read the docs

docs/features/middlewareinjection.rst

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+Middleware Injection and Overrides
+==================================
+
+Warning use with caution. If you are seeing any exceptions or strange behavior in your middleware 
+pipeline and you are using any of the following. Remove them and try again!
+
+When setting up Ocelot in your Startup.cs you can provide some additonal middleware 
+and override middleware. This is done as follos.
+
+.. code-block:: csharp
+
+    var configuration = new OcelotMiddlewareConfiguration
+    {
+        PreErrorResponderMiddleware = async (ctx, next) =>
+        {
+            await next.Invoke();
+        }
+    };
+
+    app.UseOcelot(configuration);
+
+In the example above the provided function will run before the first piece of Ocelot middleware. 
+This allows a user to supply any behaviours they want before and after the Ocelot pipeline has run.
+This means you can break everything so use at your own pleasure!
+
+The user can set functions against the following.
+
+* PreErrorResponderMiddleware - Already explained above.
+
+* PreAuthenticationMiddleware - This allows the user to run pre authentication logic and then call Ocelot's authentication middleware.
+
+* AuthenticationMiddleware - This overrides Ocelots authentication middleware.
+
+* PreAuthorisationMiddleware - This allows the user to run pre authorisation logic and then call Ocelot's authorisation middleware.
+
+* AuthorisationMiddleware - This overrides Ocelots authorisation middleware.
+
+* PreQueryStringBuilderMiddleware - This alows the user to manipulate the query string on the http request before it is passed to Ocelots request creator.
+
+Obviously you can just add middleware as normal before the call to app.UseOcelot() It cannot be added
+after as Ocelot does not call the next middleware.