diff --git a/README.md b/README.md
index 26841a6..fb28b26 100644
--- a/README.md
+++ b/README.md
@@ -28,6 +28,8 @@ or
 
 **Don't forget to change `your_secret_key` to your secret key (without quote)**
 
+**You can look at `sample.env` for more information and others environment variables to set.**
+
 4. Run these commands
 ```bash
 python manage.py migrate
diff --git a/mysite/settings.py b/mysite/settings.py
index 7a27f5c..3906c9f 100644
--- a/mysite/settings.py
+++ b/mysite/settings.py
@@ -11,7 +11,7 @@ https://docs.djangoproject.com/en/4.2/ref/settings/
 """
 
 from pathlib import Path
-from decouple import config
+from decouple import config, Csv
 
 # Build paths inside the project like this: BASE_DIR / 'subdir'.
 BASE_DIR = Path(__file__).resolve().parent.parent
@@ -20,14 +20,15 @@ BASE_DIR = Path(__file__).resolve().parent.parent
 # Quick-start development settings - unsuitable for production
 # See https://docs.djangoproject.com/en/4.2/howto/deployment/checklist/
 
-# SECURITY WARNING: keep the secret key used in production secret!
-SECRET_KEY = config('SECRET_KEY', default='fake-secret-key')
+#! SECURITY WARNING: keep the secret key used in production secret!
+SECRET_KEY = config('SECRET_KEY', default='k2pd1p)zwe0qy0k25=sli+7+n^vd-0h*&6vga6oldq=781+7qw')
 
-# SECURITY WARNING: don't run with debug turned on in production!
-DEBUG = True
+#! SECURITY WARNING: don't run with debug turned on in production!
+DEBUG = config('DEBUG', default=False, cast=bool)
 
-ALLOWED_HOSTS = []
+ALLOWED_HOSTS = config('ALLOWED_HOSTS', default='*', cast=Csv())
 
+TIME_ZONE = config('TIME_ZONE', default='Asia/Bangkok', cast=str)
 
 # Application definition
 
diff --git a/polls/migrations/0002_question_end_date_alter_question_pub_date.py b/polls/migrations/0002_question_end_date_alter_question_pub_date.py
new file mode 100644
index 0000000..56fe44f
--- /dev/null
+++ b/polls/migrations/0002_question_end_date_alter_question_pub_date.py
@@ -0,0 +1,24 @@
+# Generated by Django 4.2.4 on 2023-09-05 13:47
+
+from django.db import migrations, models
+import django.utils.timezone
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('polls', '0001_initial'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='question',
+            name='end_date',
+            field=models.DateTimeField(null=True, verbose_name='date ended'),
+        ),
+        migrations.AlterField(
+            model_name='question',
+            name='pub_date',
+            field=models.DateTimeField(default=django.utils.timezone.now, verbose_name='date published'),
+        ),
+    ]
diff --git a/polls/models.py b/polls/models.py
index 7252b32..63e2c0d 100644
--- a/polls/models.py
+++ b/polls/models.py
@@ -26,7 +26,8 @@ class Question(models.Model):
     """
 
     question_text = models.CharField(max_length=200)
-    pub_date = models.DateTimeField("date published")
+    pub_date = models.DateTimeField("date published", default=timezone.now)
+    end_date = models.DateTimeField("date ended", null=True)
 
     def was_published_recently(self):
         """
@@ -53,6 +54,29 @@ class Question(models.Model):
         """
         return self.question_text
 
+    def is_published(self):
+        """
+        Checks if the question is published or not.
+
+        Returns:
+            bool: True if the question is published, else False.
+        """
+        now = timezone.now()
+        return now >= self.pub_date
+
+    def can_vote(self):
+        """
+        Checks if the question can be voted on or not.
+
+        Returns:
+            bool: True if the question is published and not ended, else False.
+        """
+        now = timezone.now()
+        if self.end_date is None:
+            return self.pub_date <= now
+        else:
+            return self.pub_date <= now <= self.end_date
+
 
 class Choice(models.Model):
     """
diff --git a/polls/static/polls/style.css b/polls/static/polls/style.css
deleted file mode 100644
index e69de29..0000000
diff --git a/polls/templates/polls/home.html b/polls/templates/polls/home.html
index ad8a1c8..14a995a 100644
--- a/polls/templates/polls/home.html
+++ b/polls/templates/polls/home.html
@@ -10,7 +10,7 @@
     </section>
     <section class="polls-section">
         <h2>Recent Polls</h2>
-        <p class="total-polls">Total number of polls: {{ total_polls }}</p>
+        <p class="total-polls">Total number of polls: {{ total_open_polls }}</p>
         <div class="poll-cards">
             {% if latest_question_list %}
                 {% for question in latest_question_list %}
diff --git a/polls/tests.py b/polls/tests.py
index d740da3..d378745 100644
--- a/polls/tests.py
+++ b/polls/tests.py
@@ -37,6 +37,64 @@ class QuestionModelTests(TestCase):
         self.assertIs(recent_question.was_published_recently(), True)
 
 
+    def test_is_published_with_future_question(self):
+        """
+        is_published() should return False for questions whos pub_date is in the
+        future.
+        """
+        future_date = timezone.now() + datetime.timedelta(days=30)
+        future_question = Question(pub_date=future_date)
+        self.assertIs(future_question.is_published(), False)
+
+    def test_is_published_with_past_question(self):
+        """
+        is_published() should return True for questions whose pub_date is in the
+        past.
+        """
+        past_date = timezone.now() - datetime.timedelta(days=1)
+        past_question = Question(pub_date=past_date)
+        self.assertIs(past_question.is_published(), True)
+
+    def test_can_vote_with_question_not_ended(self):
+        """
+        can_vote() should return True for questions that are published and have not
+        ended.
+        """
+        pub_date = timezone.now() - datetime.timedelta(hours=1)
+        end_date = timezone.now() + datetime.timedelta(hours=1)
+        question = Question(pub_date=pub_date, end_date=end_date)
+        self.assertIs(question.can_vote(), True)
+
+    def test_can_vote_with_question_ended(self):
+        """
+        can_vote() should return False for questions that are published but have
+        ended.
+        """
+        pub_date = timezone.now() - datetime.timedelta(hours=2)
+        end_date = timezone.now() - datetime.timedelta(hours=1)
+        question = Question(pub_date=pub_date, end_date=end_date)
+        self.assertIs(question.can_vote(), False)
+
+    def test_can_vote_with_question_no_end_date(self):
+        """
+        can_vote() should return True for questions that are published and have no
+        specified end date.
+        """
+        pub_date = timezone.now() - datetime.timedelta(hours=1)
+        question = Question(pub_date=pub_date, end_date=None)
+        self.assertIs(question.can_vote(), True)
+
+    def test_can_vote_with_question_ending_in_future(self):
+        """
+        can_vote() should return True for questions that are published and
+        the current time is within the allowed voting period.
+        """
+        pub_date = timezone.now() - datetime.timedelta(hours=1)
+        end_date = timezone.now() + datetime.timedelta(hours=2)
+        question = Question(pub_date=pub_date, end_date=end_date)
+        self.assertIs(question.can_vote(), True)
+
+
 def create_question(question_text, days):
     """
     Create a question with the given `question_text` and published the
diff --git a/polls/views.py b/polls/views.py
index 6180804..4c058fa 100644
--- a/polls/views.py
+++ b/polls/views.py
@@ -17,8 +17,14 @@ class HomeView(TemplateView):
 
     def get_context_data(self, **kwargs):
         context = super().get_context_data(**kwargs)
-        context['latest_question_list'] = Question.objects.filter(pub_date__lte=timezone.now()).order_by("-pub_date")[:5]
-        context['total_polls'] = Question.objects.count()
+        all_questions = Question.objects.all()
+        #* Check if the question is published and can be voted. Then, sort by pub_date
+        published_questions = [q for q in all_questions if q.is_published() and q.can_vote()]
+        latest_published_questions = sorted(published_questions, key=lambda q: q.pub_date, reverse=True)[:5]
+
+        context['latest_question_list'] = latest_published_questions
+        context['total_open_polls'] = sum(1 for q in published_questions if q.end_date is None)
+        context['total_polls'] = all_questions.count()
         return context
 
 
diff --git a/requirements.txt b/requirements.txt
index 63393f6..08e2adf 100644
Binary files a/requirements.txt and b/requirements.txt differ
diff --git a/sample.env b/sample.env
new file mode 100644
index 0000000..c5af6b1
--- /dev/null
+++ b/sample.env
@@ -0,0 +1,10 @@
+# Copy this file to .env and edit the values
+# Create a secret key using (todo: how to create a secret key?)
+SECRET_KEY = secret-key-value-without-quotes
+# Set DEBUG to True for development, False for actual use
+DEBUG = False
+# ALLOWED_HOSTS is a comma-separated list of hosts that can access the app.
+# You can use wildcard chars (*) and IP addresses. Use * for any host.
+ALLOWED_HOSTS = *.ku.th, localhost, 127.0.0.1, ::1
+# Your timezone
+TIME_ZONE = Asia/Bangkok
\ No newline at end of file