title: how to add custom error messages in modelform widgets in django
body: <p>these are fields of the model form
      class Meta:</p>
  
  <pre><code>    model = Employee
      exclude = ('user', 'created_by', 'is_deleted', 'created')
  </code></pre>
  
  <p>theses are the widgets</p>
  
  <pre><code>    widgets = {
          'first_name': forms.TextInput(attrs={'placeholder': _('First name')}),
          'last_name': forms.TextInput(attrs={'placeholder': _('Last name')}),
          'house_name': forms.TextInput(attrs={'placeholder': _('House name / flat No')}),
          'street_name': forms.TextInput(attrs={'placeholder': _('Street Name / No')}),
          'locality_name': forms.TextInput(attrs={'placeholder': _('Locality Name / No')}),
          'pin_code': forms.TextInput(attrs={'placeholder': _('Zip Code')}),
      }
  </code></pre>