social_media_platform/application/forms.py

from django import forms
from datetime import datetime

from .models import Post, CustomUser
from django.forms import ModelForm, ValidationError

from taggit.forms import *

#extended code customised
#import from https://tutorial.djangogirls.org/en/django_forms/
class PostForm(forms.ModelForm):

    class Meta:
        model = Post
        fields = ('title', 'text', 'published_date','tags')


class NewTagForm(forms.ModelForm):
    tags = TagField()

    class Meta:
        model = CustomUser
        fields = ['tags']