update README

README.md

@@ -45,20 +45,21 @@ intend to run `google_auth_proxy` on.
 ## Command Line Options
 
 ```
-Usage of ./google_auth_proxy:
+Usage of google_auth_proxy:
   -authenticated-emails-file="": authenticate against emails via file (one per line)
   -client-id="": the Google OAuth Client ID: ie: "123456.apps.googleusercontent.com"
   -client-secret="": the OAuth Client Secret
-  -cookie-domain="": an optional cookie domain to force cookies to
-  -cookie-expire=168h: expire timeframe for cookie
+  -config="": path to config file
+  -cookie-domain="": an optional cookie domain to force cookies to (ie: .yourcompany.com)
+  -cookie-expire=168h0m0s: expire timeframe for cookie
   -cookie-https-only=false: set HTTPS only cookie
   -cookie-secret="": the seed string for secure cookies
-  -google-apps-domain=[]: authenticate against the given google apps domain (may be given multiple times)
+  -google-apps-domain=: authenticate against the given Google apps domain (may be given multiple times)
   -htpasswd-file="": additionally authenticate against a htpasswd file. Entries must be created with "htpasswd -s" for SHA encryption
   -http-address="127.0.0.1:4180": <addr>:<port> to listen on for HTTP clients
-  -pass-basic-auth=true: pass HTTP Basic Auth information to upstream
+  -pass-basic-auth=true: pass HTTP Basic Auth, X-Forwarded-User and X-Forwarded-Email information to upstream
   -redirect-url="": the OAuth Redirect URL. ie: "https://internalapp.yourcompany.com/oauth2/callback"
-  -upstream=[]: the http url(s) of the upstream endpoint. If multiple, routing is based on path
+  -upstream=: the http url(s) of the upstream endpoint. If multiple, routing is based on path
   -version=false: print version string
 ```