code: def markdown_search_user(request):
      
      data = {}
      username = request.GET.get('username')
      if username is not None \
              and username != '' \
              and ' ' not in username:
          users = User.objects.filter(
              Q(username__icontains=username)
          ).filter(is_active=True)
          if users.exists():
              data.update({
                  'status': 200,
                  'data': [{'username': u.username} for u in users]
              })
              return HttpResponse(
                  json.dumps(data, cls=LazyEncoder),
                  content_type='application/json')
          data.update({
              'status': 204,
              'error': _('No users registered as `%(username)s` '
                         'or user is unactived.') % {'username': username}
          })
      else:
          data.update({
              'status': 204,
              'error': _('Validation Failed for field `username`')
          })
      return HttpResponse(
          json.dumps(data, cls=LazyEncoder),
          content_type='application/json')
docs: Json usernames of the users registered & actived.
  
      url(method=get):
          /martor/search-user/?username={username}
  
      Response:
          error:
              - `status` is status code (204)
              - `error` is error message.
          success:
              - `status` is status code (204)
              - `data` is list dict of usernames.
                  { 'status': 200,
                    'data': [
                      {'usernane': 'john'},
                      {'usernane': 'albert'}]
                  }