Add custom CSS styling to model form django

I am using a bootstrap variant to help style a model form. There is a certain class I would like one of the fields to be and I have read around on the subject and the general consensus is to add a widget to the ModelForm’s meta, like I tried below:

forms.py

class EmailForm(forms.ModelForm):
    class Meta:
        model = MarketingEmails
        fields = ['messageid','subject','body','name','altsubject','utm_source','utm_content','utm_campaign',]
        widgets = {
            'body': Textarea(attrs={'class': 'summernote'}),
        }

However this doesn’t seem to render onto my template, which is:

<div class="row">
<div class="col-sm-6">
    <form method="POST" class="post-form" action ="">
    {% csrf_token %}        
        <p><label for="id_subject">Subject</label>
        <input class="form-control" id="id_subject" type="text" name="subject" maxlength="1000" value="{{rows.subject}}"required /></p>

        <p><label for="id_name">Name</label>
        <input class="form-control" id="id_name" type="text" name="name" maxlength="1000" value="{{rows.name}}"required /></p>

        <p><label for="id_body">Body</label>
        <input class="form-control" id="id_body" type="text" name="body" maxlength="1000" value="{{rows.body}}"required /></p>

        <p><label for="id_altsubject">Alt Subject</label>
        <input class="form-control" id="id_altsubject" type="text" name="altsubject" maxlength="1000" value="{{rows.altsubject}}"required /></p>

        <p><label for="id_utm_source">utm_source</label>
        <input class="form-control" id="id_utm_source" type="text" name="utm_source" maxlength="1000" value="{{rows.utm_source}}"required /></p>

        <p><label for="id_utm_content">utm_content</label>
        <input class="form-control" id="id_utm_content" type="text" name="utm_content" maxlength="1000" value="{{rows.utm_content}}"required /></p>

        <p><label for="id_utm_campaign">utm_campaign</label>
        <input class="form-control" id="id_utm_campaign" type="text" name="utm_campaign" maxlength="1000" value="{{rows.utm_campaign}}"required /></p>

        <button type="submit" class="save btn btn-default">Save</button>

    </form>
</div>

Is there another way to do this or is there something I have done wrong in my code?

UPDATE I have followed the suggested of Jacek and now it is styled but the information is no longer displaying, this is my new code:

forms.py:

class EmailForm(forms.ModelForm):
subject = forms.CharField(
    label = 'Subject',
    max_length = 2000,
    required = True,
    widget = forms.TextInput(
        attrs = {'class': 'summernote', 'name': 'subject'}
        )
    )

... 
class Meta:
    model = MarketingEmails
    fields = ['messageid','subject','body','name','altsubject','utm_source','utm_content','utm_campaign',]

views.py:

def emailinfo(request, pk):
if request.session.has_key('shortname'):
    shortname =  request.session['shortname']
    form = MarketingEmails.objects.filter(messageid =pk).get()
    if request.method == 'GET':
        form = EmailForm(instance=form)
        return render(request, 'marketingemails/emailinfo.html',{'shortname': shortname, 'form': form})

    else:
        form = EmailForm(request.POST,instance=form)
        if form.is_valid():
            return redirect('marketingemails:emailinfo', pk = form.messageid)

    return render(request, 'marketingemails/emailinfo.html',{'shortname': shortname, 'form': form})
else:
    return HttpResponseRedirect(reverse('common:login'))    

html:

<div class="row">
<div class="col-sm-6">
    <form method="POST" action ="">
    {% csrf_token %}        
    {% for field in form %}
        {{ field.label_tag }}
        {{ field }}

        {% if field.help_text %}
            {{ field.help_text }}
        {% endif %}

        {% for error in field.errors %}
            {{ error }}
        {% endfor %}

    {% endfor %}
    <button type="submit" class="btn btn-primary">Submit</button>

    </form>
</div>

Answer

Try this:

forms.py

class EmailForm(forms.ModelForm):
    ...
    subject = forms.CharField(
        label = 'Subject',
        max_length = 1000,
        required = True,
        widget = forms.TextInput(
            attrs = {'class': 'summernote', 'name': 'subject'}
        )
    )   

    body = forms.CharField(
        label = 'Body',
        max_length = 1000,
        required = True,
        widget = forms.TextInput(
            attrs = {'class': 'summernote', 'name': 'body'}
        )
    )   
    ...

    class Meta:
        model = MarketingEmails
        fields = ('messageid','subject','body','name', ... )

view.py

from django.shortcuts import render
from your_app_path.forms import EmailForm

def fname(request):
    ...
    marketing = MarketingEmails.objects.get(...)

    form = EmailForm(instance=marketing) 
    ...

    return render(request, 'yourview.html', { 'form': form })

yourview.html

<form action="" method="post">
  {% csrf_token %}
  {% for field in form %}
    {{ field.label_tag }}
    {{ field }}

    {% if field.help_text %}
      {{ field.help_text }}
    {% endif %}

    {% for error in field.errors %}
      {{ error }}
    {% endfor %}

  {% endfor %}
  <button type="submit" class="btn btn-primary">Submit</button>
</form>