use virtual-dom to implement functionality for invite form

src/js/components/inviteForm.js

@@ -0,0 +1,40 @@
+'use strict';
+
+var {h} = require('virtual-dom');
+var classList = require('../util/classList');
+
+function render(props, state) {
+  var emailInput = h('input', {
+    className: classList({
+      'input': true,
+      'has-success': state.submitted,
+      'has-error': state.error
+    }),
+    type: 'text',
+    name: 'email',
+    placeholder: 'Email',
+    value: state.email,
+    onkeydown: props.onChange
+  });
+
+  var submitButton = h('button', {
+    className: 'btn btn__submit',
+    type: 'submit',
+    title: 'Lähetä',
+    disabled: state.error || state.submitted
+  }, '⏎');
+
+  return h('form', {
+    className: classList({
+      'invite-form': true,
+      'has-success': state.submitted,
+      'has-error': state.error
+    }),
+    onsubmit: props.onSubmit
+  }, [
+    emailInput,
+    submitButton
+  ]);
+}
+
+module.exports = render;