feat: created AppState to keep track of the state of the application

src/main/java/edu/group5/app/model/AppState.java

@@ -1,4 +1,36 @@
 package edu.group5.app.model;
 
+import edu.group5.app.model.organization.Organization;
+import edu.group5.app.model.user.User;
+
+import java.math.BigDecimal;
+
 public class AppState {
+  private User currentUser;
+  private BigDecimal currentDonationAmount;
+  private Organization currentOrganization;
+
+  public User getCurrentUser() {
+    return this.currentUser;
+  }
+
+  public void setCurrentUser(User user) {
+    this.currentUser = user;
+  }
+
+  public Organization getCurrentOrganization() {
+    return this.currentOrganization;
+  }
+
+  public void setCurrentOrganization(Organization organization) {
+    this.currentOrganization = organization;
+  }
+
+  public BigDecimal getCurrentDonationAmount() {
+    return this.currentDonationAmount;
+  }
+
+  public void setCurrentDonationAmount(BigDecimal amount) {
+    this.currentDonationAmount = amount;
+  }
 }