add Cypress spec

Author: bahmutov

cypress.json

@@ -0,0 +1,5 @@
+{
+  "supportFile": false,
+  "pluginsFile": false,
+  "fixturesFolder": false
+}

cypress/integration/spec.js

@@ -0,0 +1,9 @@
+/// <reference types="cypress" />
+it('loads page', () => {
+  if (Cypress.config('baseUrl')) {
+    cy.visit('/')
+  } else {
+    cy.visit('public/index.html')
+  }
+  cy.contains('Placeholder').should('be.visible')
+})