diff --git a/.vscode/c_cpp_properties.json b/.vscode/c_cpp_properties.json
index 779ce6d..238b7e5 100644
--- a/.vscode/c_cpp_properties.json
+++ b/.vscode/c_cpp_properties.json
@@ -4,7 +4,8 @@
             "name": "Linux",
             "includePath": [
                 "${workspaceFolder}/**",
-                "/usr/include/qt"
+                "/usr/include/qt",
+                "/usr/include/qt/QtWidgets"
             ],
             "defines": [],
             "compilerPath": "/usr/bin/clang",
diff --git a/src/core/CMakeLists.txt b/src/core/CMakeLists.txt
index 78113b5..2c7f713 100644
--- a/src/core/CMakeLists.txt
+++ b/src/core/CMakeLists.txt
@@ -3,11 +3,6 @@
 find_package(Boost 1.62 COMPONENTS date_time REQUIRED)
 find_package(SQLite3 REQUIRED)
 
-#set(CORE_HEADERS
-#    entity.h
-#    database.h
-#)
-
 set(CORE_SOURCES
     database.cpp
     entity.cpp
@@ -19,4 +14,5 @@ set(CORE_SOURCES
 
 add_library(core STATIC ${CORE_SOURCES})
 target_link_libraries(core Boost::boost Boost::date_time)
-target_link_libraries(core sqlite3)
\ No newline at end of file
+target_link_libraries(core sqlite3)
+target_include_directories(core PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
\ No newline at end of file
diff --git a/src/gui/kima2.cpp b/src/gui/kima2.cpp
index 372e273..cb210ef 100644
--- a/src/gui/kima2.cpp
+++ b/src/gui/kima2.cpp
@@ -1,5 +1,7 @@
 #include "mainwindow.h"
 
+#include <memory>
+
 #include <QApplication>
 
 
@@ -9,8 +11,8 @@ int main(int argc, char* argv[])
 
     QApplication kimaApp{argc, argv};
 
-    MainWindow mainWin{};
-    mainWin.show();
+    auto mainWin = std::make_unique<MainWindow>();
+    mainWin->show();
 
     return kimaApp.exec();
 }
diff --git a/src/gui/mainwindow.cpp b/src/gui/mainwindow.cpp
index c94ac19..d352cfe 100644
--- a/src/gui/mainwindow.cpp
+++ b/src/gui/mainwindow.cpp
@@ -2,5 +2,10 @@
 
 MainWindow::MainWindow()
 {
-    ui.setupUi(this);
-}
\ No newline at end of file
+    ui_.setupUi(this);
+
+    connect(ui_.actionQuit, &QAction::triggered, qApp, QApplication::quit);
+
+    marketplace_ = std::make_unique<Marketplace>();
+}
+
diff --git a/src/gui/mainwindow.h b/src/gui/mainwindow.h
index 2cc3dad..943382c 100644
--- a/src/gui/mainwindow.h
+++ b/src/gui/mainwindow.h
@@ -1,9 +1,13 @@
 #ifndef MAINWINDOW_H
 #define MAINWINDOW_H
 
+#include <marketplace.h>
+
 #include "ui_mainwindow.h"
 #include <QMainWindow>
 
+#include <memory>
+
 class MainWindow : public QMainWindow
 {
     Q_OBJECT
@@ -12,7 +16,8 @@ class MainWindow : public QMainWindow
     MainWindow();
 
     private:
-        Ui::MainWindow ui;
+        Ui::MainWindow ui_;
+        std::unique_ptr<Marketplace> marketplace_;
 };
 
 #endif
\ No newline at end of file
diff --git a/src/gui/mainwindow.ui b/src/gui/mainwindow.ui
index ca4bfd5..79a4517 100644
--- a/src/gui/mainwindow.ui
+++ b/src/gui/mainwindow.ui
@@ -23,8 +23,36 @@
      <height>24</height>
     </rect>
    </property>
+   <widget class="QMenu" name="menu_Datei">
+    <property name="title">
+     <string>&amp;Datei</string>
+    </property>
+    <addaction name="actionQuit"/>
+   </widget>
+   <widget class="QMenu" name="menu_Edit">
+    <property name="title">
+     <string>&amp;Bearbeiten</string>
+    </property>
+    <addaction name="actionEditSeller"/>
+   </widget>
+   <addaction name="menu_Datei"/>
+   <addaction name="menu_Edit"/>
   </widget>
   <widget class="QStatusBar" name="statusbar"/>
+  <action name="actionQuit">
+   <property name="icon">
+    <iconset theme="application-exit">
+     <normaloff>.</normaloff>.</iconset>
+   </property>
+   <property name="text">
+    <string>&amp;Beenden</string>
+   </property>
+  </action>
+  <action name="actionEditSeller">
+   <property name="text">
+    <string>&amp;Verkäufer...</string>
+   </property>
+  </action>
  </widget>
  <resources/>
  <connections/>
diff --git a/src/gui/sellerdialog.ui b/src/gui/sellerdialog.ui
new file mode 100644
index 0000000..b789849
--- /dev/null
+++ b/src/gui/sellerdialog.ui
@@ -0,0 +1,115 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<ui version="4.0">
+ <class>sellerDialog</class>
+ <widget class="QDialog" name="sellerDialog">
+  <property name="windowModality">
+   <enum>Qt::NonModal</enum>
+  </property>
+  <property name="geometry">
+   <rect>
+    <x>0</x>
+    <y>0</y>
+    <width>400</width>
+    <height>300</height>
+   </rect>
+  </property>
+  <property name="windowTitle">
+   <string>Verkäufer Dialog</string>
+  </property>
+  <property name="modal">
+   <bool>true</bool>
+  </property>
+  <layout class="QVBoxLayout" name="verticalLayout">
+   <item>
+    <layout class="QHBoxLayout" name="horizontalLayout">
+     <item>
+      <widget class="QTableView" name="tableView"/>
+     </item>
+     <item>
+      <layout class="QVBoxLayout" name="verticalLayout_2">
+       <item>
+        <widget class="QPushButton" name="newButton">
+         <property name="text">
+          <string>Neu</string>
+         </property>
+        </widget>
+       </item>
+       <item>
+        <widget class="QPushButton" name="editButton">
+         <property name="text">
+          <string>Bearbeiten</string>
+         </property>
+        </widget>
+       </item>
+       <item>
+        <widget class="QPushButton" name="deleteButton">
+         <property name="text">
+          <string>Löschen</string>
+         </property>
+        </widget>
+       </item>
+       <item>
+        <spacer name="verticalSpacer">
+         <property name="orientation">
+          <enum>Qt::Vertical</enum>
+         </property>
+         <property name="sizeHint" stdset="0">
+          <size>
+           <width>20</width>
+           <height>40</height>
+          </size>
+         </property>
+        </spacer>
+       </item>
+      </layout>
+     </item>
+    </layout>
+   </item>
+   <item>
+    <widget class="QDialogButtonBox" name="buttonBox">
+     <property name="orientation">
+      <enum>Qt::Horizontal</enum>
+     </property>
+     <property name="standardButtons">
+      <set>QDialogButtonBox::Cancel|QDialogButtonBox::Ok</set>
+     </property>
+    </widget>
+   </item>
+  </layout>
+ </widget>
+ <resources/>
+ <connections>
+  <connection>
+   <sender>buttonBox</sender>
+   <signal>accepted()</signal>
+   <receiver>sellerDialog</receiver>
+   <slot>accept()</slot>
+   <hints>
+    <hint type="sourcelabel">
+     <x>248</x>
+     <y>254</y>
+    </hint>
+    <hint type="destinationlabel">
+     <x>157</x>
+     <y>274</y>
+    </hint>
+   </hints>
+  </connection>
+  <connection>
+   <sender>buttonBox</sender>
+   <signal>rejected()</signal>
+   <receiver>sellerDialog</receiver>
+   <slot>reject()</slot>
+   <hints>
+    <hint type="sourcelabel">
+     <x>316</x>
+     <y>260</y>
+    </hint>
+    <hint type="destinationlabel">
+     <x>286</x>
+     <y>274</y>
+    </hint>
+   </hints>
+  </connection>
+ </connections>
+</ui>