Add functionality to add allowance (#101)

closes #69
closes #107

Reviewed-on: #101

frontend/allowance-planner-v2/src/app/pages/add-allowance/add-allowance.page.ts

@@ -0,0 +1,51 @@
+import { Location } from '@angular/common';
+import { Component } from '@angular/core';
+import { FormBuilder, FormGroup, Validators } from '@angular/forms';
+import { ActivatedRoute, Router } from '@angular/router';
+import { AllowanceService } from 'src/app/services/allowance.service';
+
+@Component({
+  selector: 'app-add-allowance',
+  templateUrl: './add-allowance.page.html',
+  styleUrls: ['./add-allowance.page.scss'],
+  standalone: false,
+})
+export class AddAllowancePage {
+  public form: FormGroup;
+  public goalId: number;
+  public userId: number;
+  public isAddMode = true;
+// Marcus' first comment
+//            b    ........a`.OK  ø¶Ópppppppp--P09OP
+
+
+  constructor(
+    private allowanceService: AllowanceService,
+    private route: ActivatedRoute,
+    private formBuilder: FormBuilder,
+    private router: Router,
+    private location: Location
+  ) {
+    this.userId = this.route.snapshot.params['id'];
+    this.goalId = this.route.snapshot.params['goalId'];
+
+    this.form = this.formBuilder.group({
+      amount: ['', Validators.required],
+      description: ['', Validators.required]
+    });
+  }
+
+  changeAllowance() {
+    this.allowanceService.addOrSpendAllowance(
+      this.goalId,
+      this.userId,
+      this.form.value.amount,
+      this.form.value.description
+    );
+    this.router.navigate(['/tabs/allowance', this.userId]);
+  }
+
+  navigateBack() {
+    this.location.back();
+  }
+}