Can update following status of a group

lib/ui/widgets/group_following_widget.dart

@@ -0,0 +1,55 @@
+import 'package:comunic/helpers/groups_helper.dart';
+import 'package:comunic/models/group.dart';
+import 'package:comunic/ui/widgets/safe_state.dart';
+import 'package:comunic/utils/intl_utils.dart';
+import 'package:comunic/utils/ui_utils.dart';
+import 'package:flutter/material.dart';
+
+/// Group following status widget
+///
+/// @author Pierre Hubert
+
+class GroupFollowingWidget extends StatefulWidget {
+  final Group group;
+  final Function() onUpdated;
+
+  const GroupFollowingWidget(
+      {Key key, @required this.group, @required this.onUpdated})
+      : assert(group != null),
+        assert(onUpdated != null),
+        super(key: key);
+
+  @override
+  _GroupFollowingWidgetState createState() => _GroupFollowingWidgetState();
+}
+
+class _GroupFollowingWidgetState extends SafeState<GroupFollowingWidget> {
+  Group get _group => widget.group;
+
+  @override
+  Widget build(BuildContext context) {
+    if (!_group.isAtLeastMember) return Container();
+
+    return InkWell(
+      child: Text(
+        _group.following ? tr("Following") : tr("Follow"),
+        style: TextStyle(color: Colors.blue),
+      ),
+      onTap: () => _toggleFollowing(),
+    );
+  }
+
+  /// Toggle following status
+  void _toggleFollowing() async {
+    if (!await GroupsHelper().setFollowing(_group.id, !_group.following)) {
+      showSimpleSnack(context, tr("Could not update following status!"));
+      return;
+    }
+
+    setState(() {
+      _group.following = !_group.following;
+
+      this.widget.onUpdated();
+    });
+  }
+}