add category and global meta (#438)

server/src/main/kotlin/suwayomi/tachidesk/global/model/table/GlobalMetaTable.kt

@@ -0,0 +1,18 @@
+package suwayomi.tachidesk.global.model.table
+
+/*
+ * Copyright (C) Contributors to the Suwayomi project
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+import org.jetbrains.exposed.dao.id.IntIdTable
+
+/**
+ * Metadata storage for clients, server/global level.
+ */
+object GlobalMetaTable : IntIdTable() {
+    val key = varchar("key", 256)
+    val value = varchar("value", 4096)
+}