Add README

README.md

+== Phab userinfo ==
+
+Small helper to translate the userinfo endpoint provided by phabricator into a
+more standard json format as support by e.g. the grafana generic oauth
+authentication helper
+
+```
+phab-userinfo 0.1.0
+
+USAGE:
+    phab-userinfo [ARGS]
+
+FLAGS:
+    -h, --help       Prints help information
+    -V, --version    Prints version information
+
+ARGS:
+    <url>      [env: URL=]  [default: https://phabricator.collabora.com/api/user.whoami]
+    <port>     [env: PORT=]  [default: 8080]
+```