sso: expire tokens after usage

db/20190420231030-sso-tokens.sql

@@ -0,0 +1,6 @@
+CREATE TABLE IF NOT EXISTS ssoTokens (
+  token                    TEXT          NOT NULL  UNIQUE  PRIMARY KEY      ,
+  domain                   TEXT          NOT NULL                           ,
+  commenterToken           TEXT          NOT NULL                           ,
+  creationDate             TIMESTAMP     NOT NULL
+);