old_contents: from django import forms
  from django.contrib.admin import widgets
  from datetimewidget.widgets import DateTimeWidget
  from .models import Event
  
  
  class LoginForm(forms.Form):
      username = forms.CharField(label='Nazwa użytkownika')
      password = forms.CharField(label='Hasło', widget=forms.PasswordInput())
  
  
  data_time_options = {
      'format': 'dd-mm-yyyy HH:ii'
  }
  
  def dt_widget():
      return DateTimeWidget(
          bootstrap_version=3,
          usel10n=True,
          options=data_time_options
      )
  
  
  class EventForm(forms.ModelForm):
  
      class Meta:
          model = Event
          fields = (
              'title', 'description',
              'categories', 'start_time',
              'end_time', 'image', 'place',
          )
          widgets = {
              'start_time': dt_widget(),
              'end_time': dt_widget(),
          }
  
new_contents: from django import forms
  from django.contrib.admin import widgets
  from datetimewidget.widgets import DateTimeWidget
  from .models import Event
  
  
  class LoginForm(forms.Form):
      username = forms.CharField(label='Nazwa użytkownika')
      password = forms.CharField(label='Hasło', widget=forms.PasswordInput())
  
  
  data_time_options = {
      'format': 'dd-mm-yyyy HH:ii'
  }
  
  def dt_widget():
      return DateTimeWidget(
          bootstrap_version=3,
          usel10n=True,
          options=data_time_options
      )
  
  
  class EventForm(forms.ModelForm):
  
      class Meta:
          model = Event
          fields = (
              'title', 'place',
              'description', 'categories',
              'start_time', 'end_time',
              'image', 'url',
          )
          widgets = {
              'start_time': dt_widget(),
              'end_time': dt_widget(),
          }
  
subject: Change fields order and add field url.