auth: token_secret can be set as env variable

auth/auth.go

@@ -41,7 +41,7 @@
 
 // TokenOptions holds options related to the JWT.
 type TokenOptions struct {
-	Secret             string             `long:"token-secret" ini-name:"token-secret" description:"HMAC secret for signing/verifying JWT"`
+	Secret             string             `long:"token-secret" ini-name:"token-secret" env:"AUTH_TOKEN_SECRET" description:"HMAC secret for signing/verifying JWT"`
 	ExpirationOpt      func(string) error `long:"token-expiration" ini-name:"token-expiration" required:"false" description:"Expiration time of the generated tokens" default:"5m"`
 	Expiration         time.Duration      `no-flag:"t"`
 	CookieDomain       string             `long:"cookie-domain" ini-name:"cookie-domain" description:"The domain used in cookies, must match the public-facing server host name"`