add preffered_username to idToken

Signed-off-by: Nandor Kracser <bonifaido@gmail.com>

storage/sql/migrate.go

@@ -190,4 +190,16 @@ var migrations = []migration{
 			);`,
 		},
 	},
+	{
+		stmts: []string{`
+			alter table auth_code
+				add column claims_preferred_username text not null default '';`,
+			`
+			alter table auth_request
+				add column claims_preferred_username text not null default '';`,
+			`
+			alter table refresh_token
+				add column claims_preferred_username text not null default '';`,
+		},
+	},
 }