Added schedule post dropdown component and container, styles

app/javascript/gabsocial/features/compose/containers/schedule_post_dropdown_container.js

@@ -0,0 +1,22 @@
+import { connect } from 'react-redux';
+import SchedulePostDropdown from '../components/schedule_post_dropdown';
+import { changeScheduledAt } from '../../../actions/compose';
+import { openModal } from '../../../actions/modal';
+import { me } from '../../../initial_state';
+
+const mapStateToProps = state => ({
+  date: state.getIn(['compose', 'scheduled_at']),
+  isPro: state.getIn(['accounts', me, 'is_pro']),
+});
+
+const mapDispatchToProps = dispatch => ({
+  setScheduledAt (date) {
+    dispatch(changeScheduledAt(date));
+  },
+
+  onOpenProUpgradeModal() {
+    dispatch(openModal('PRO_UPGRADE'));
+  },
+});
+
+export default connect(mapStateToProps, mapDispatchToProps)(SchedulePostDropdown);