Add new file

README.md

+# Server side
+Download the binary, make it executable and provide parameters
+example : `./xcache-flusher -cachedir /tmp/testdir -token mysecretpassword`
+
+Server will listen on port 8080
+
+# Client side
+Client just needs to call the DELETE HTTP operation on the server URL with method `flush`. Optionnally provide authentication token in the URL.
+example:
+  * with authentication: `curl -X DELETE http://127.0.0.1:8080/flush\?token\=testos`
+  * without authentication: `curl -X DELETE http://127.0.0.1:8080/flush`
\ No newline at end of file