Feature: View a contact's previous conversation (#422)

* Add API to fetch conversations of a contact

* Add conversation list in sidebar

app/javascript/dashboard/store/modules/specs/contactConversations/getters.spec.js

@@ -0,0 +1,23 @@
+import { getters } from '../../contactConversations';
+
+describe('#getters', () => {
+  it('getContactConversation', () => {
+    const state = {
+      records: { 1: [{ id: 1, contact_id: 1, message: 'Hello' }] },
+    };
+    expect(getters.getContactConversation(state)(1)).toEqual([
+      { id: 1, contact_id: 1, message: 'Hello' },
+    ]);
+  });
+
+  it('getUIFlags', () => {
+    const state = {
+      uiFlags: {
+        isFetching: true,
+      },
+    };
+    expect(getters.getUIFlags(state)).toEqual({
+      isFetching: true,
+    });
+  });
+});