[Enhancement] Fetch previous messages in the conversation (#355)

* Fetch previous messages in the conversation

* Add specs for conversation store

* Fix codeclimate issues

* Exclude specs folder

* Exclude globally

* Fix path in exclude patterns

* Add endPoints spec

* Add snapshots for Spinner

* Add specs for actions

app/javascript/shared/components/specs/Spinner.spec.js

@@ -0,0 +1,10 @@
+import { mount } from '@vue/test-utils';
+import Spinner from '../Spinner';
+
+describe('Spinner', () => {
+  test('matches snapshot', () => {
+    const wrapper = mount(Spinner);
+    expect(wrapper.isVueInstance()).toBeTruthy();
+    expect(wrapper.element).toMatchSnapshot();
+  });
+});