feat: Creates add button component for label (#2223)

app/javascript/shared/components/ui/dropdown/AddLabel.stories.js

@@ -0,0 +1,19 @@
+import { action } from '@storybook/addon-actions';
+import AddLabel from './AddLabel';
+
+export default {
+  title: 'Components/Label/Add Button',
+  component: AddLabel,
+  argTypes: {},
+};
+
+const Template = (args, { argTypes }) => ({
+  props: Object.keys(argTypes),
+  components: { AddLabel },
+  template: '<add-label v-bind="$props" @add="onClick"></add-label>',
+});
+
+export const AddButton = Template.bind({});
+AddButton.args = {
+  onClick: action('opened'),
+};