Add forgotten M_TERMS_NOT_SIGNED error message.

src/main/java/io/kamax/mxisd/exception/TermsNotSignedException.java

@@ -0,0 +1,28 @@
+/*
+ * ma1sd - Matrix Identity Server Daemon
+ * Copyright (C) 2020 Anatoliy SAblin
+ *
+ * https://www.github.com/ma1uta/ma1sd/
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package io.kamax.mxisd.exception;
+
+public class TermsNotSignedException extends RuntimeException {
+
+    public TermsNotSignedException() {
+        super("Please accept our updated terms of service before continuing");
+    }
+}