diff -r fd8c40ff78c3 -r 824d4042c857 src/main/java/de/uapcore/lightpit/dao/postgres/PGModuleDao.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/main/java/de/uapcore/lightpit/dao/postgres/PGModuleDao.java	Sat May 09 17:01:29 2020 +0200
@@ -0,0 +1,81 @@
+/*
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
+ *
+ * Copyright 2018 Mike Becker. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *   1. Redistributions of source code must retain the above copyright
+ *      notice, this list of conditions and the following disclaimer.
+ *
+ *   2. Redistributions in binary form must reproduce the above copyright
+ *      notice, this list of conditions and the following disclaimer in the
+ *      documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+package de.uapcore.lightpit.dao.postgres;
+
+import de.uapcore.lightpit.LightPITModule;
+import de.uapcore.lightpit.dao.AbstractDao;
+import de.uapcore.lightpit.dao.ModuleDao;
+import de.uapcore.lightpit.entities.Module;
+
+import java.sql.Connection;
+import java.sql.PreparedStatement;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.util.Map;
+import java.util.Set;
+
+public final class PGModuleDao extends AbstractDao<Module> implements ModuleDao {
+
+    @Override
+    protected PreparedStatement listQuery(Connection connection) throws SQLException {
+        return connection.prepareStatement("select * from lpitcore_module");
+    }
+
+    @Override
+    protected Module mapColumns(ResultSet result) throws SQLException {
+        final var mod = new Module();
+        mod.setModID(result.getInt("modid"));
+        mod.setClassname(result.getString("classname"));
+        mod.setVisible(result.getBoolean("visible"));
+        mod.setPriority(result.getInt("priority"));
+        return mod;
+    }
+
+    @Override
+    public void syncRegisteredModuleClasses(Connection conn, Set<Map.Entry<String, LightPITModule>> moduleSet) throws SQLException {
+
+        var check = conn.prepareStatement("select visible from lpitcore_module where classname = ?");
+        var insert = conn.prepareStatement("insert into lpitcore_module (classname, visible, priority) values (?, ?, ?)");
+        insert.setBoolean(2, true);
+        // update/delete not required, we do this in the module management UI
+
+        for (Map.Entry<String, LightPITModule> modEntry : moduleSet) {
+            if (modEntry.getValue().systemModule()) continue;
+
+            check.setString(1, modEntry.getKey());
+            try (ResultSet r = check.executeQuery()) {
+                if (!r.next()) {
+                    insert.setString(1, modEntry.getKey());
+                    insert.setInt(3, modEntry.getValue().defaultPriority());
+                    insert.executeUpdate();
+                }
+            }
+        }
+    }
+}