Add users system, required for uploading new pastes

cmd/rushlink/main.go

@@ -32,6 +32,10 @@ func main() {
 		log.Fatal(errors.Wrap(err, "migrating database"))
 	}
 
+	if err := db.CreateAdminUser(database, "admin"); err != nil {
+	  log.Fatalln(err)
+	}
+
 	go rushlink.StartMetricsServer(*metricsListen, database, filestore)
 	rushlink.StartMainServer(*httpListen, database, filestore, *rootURL)
 }