Further javascript improvements

app/static/js/forms/create-contribution-form.js

@@ -0,0 +1,18 @@
+Forms.CreateContributionForm = class CreateContributionForm extends Forms.BaseForm {
+  static autoInit() {
+    let createContributionFormElements = document.querySelectorAll('.create-contribution-form');
+    for (let createContributionFormElement of createContributionFormElements) {
+      new Forms.CreateContributionForm(createContributionFormElement);
+    }
+  }
+
+  constructor(formElement) {
+    super(formElement);
+
+    this.addEventListener('requestLoad', (event) => {
+      if (event.target.status === 201) {
+        window.location.href = event.target.getResponseHeader('Location');
+      }
+    });
+  }
+};