Started implumenting a GUI for the program.

src/main/java/me/zacharias/bank/app/Main.java

@@ -0,0 +1,57 @@
+package me.zacharias.bank.app;
+
+import me.zacharias.bank.Account;
+import me.zacharias.bank.User;
+
+import javax.swing.*;
+import java.awt.*;
+
+public class Main extends JPanel {
+    public static void main(String[] args) {
+        new Main();
+    }
+    
+    JFrame frame;
+    Login login;
+    MainMenu mainManu;
+    AccountView accountView;
+    
+    Timer timer = new Timer(100, e -> {frame.repaint();});
+    
+    
+    public Main() {
+        frame = new JFrame("Bank");
+        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
+        frame.setSize(800, 600);
+        frame.setLocationRelativeTo(null);
+        
+        login = new Login(this);
+        login.setBounds(0, 0, 800, 600);
+        
+        frame.add(login);
+        
+        frame.setVisible(true);
+        timer.start();
+    }
+    
+    public void login(User user) {
+        frame.remove(login);
+        mainManu = new MainMenu(user, this);
+        frame.add(mainManu);
+        frame.setVisible(true);
+    }
+    
+    public void logout() {
+        frame.remove(mainManu);
+        login.clear();
+        frame.add(login);
+        frame.setVisible(true);
+    }
+    
+    public void showAccount(Account account) {
+        frame.remove(mainManu);
+        accountView = new AccountView(this, account);
+        frame.add(accountView);
+        frame.setVisible(true);
+    }
+}