diff --git a/Dockerfile b/Dockerfile
index ed13576..a7a6de3 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -12,6 +12,7 @@ RUN git clone https://git.kucharczyk.xyz/lukas/timetracker.git /home/timetracker
 WORKDIR /home/timetracker/app
 RUN chown -R timetracker /home/timetracker/app
 RUN poetry install
+RUN make initialize
 EXPOSE 8000
 USER timetracker
 CMD [ "python3", "src/web/manage.py", "runserver", "0.0.0.0:8000" ]
\ No newline at end of file
diff --git a/Makefile b/Makefile
index 37f714c..f3b202b 100644
--- a/Makefile
+++ b/Makefile
@@ -1,8 +1,12 @@
+.PHONY: createsuperuser
+
 all: css migrate
 
 initialize: css migrate loadplatforms
 
-css: src\input.css src\web\tracker\templates\*.html
+HTMLFILES := $(shell find src\web\tracker\templates -type f)
+
+css: src\input.css $(HTMLFILES)
 	npx tailwindcss -i .\src\input.css -o  .\src\web\tracker\static\base.css
 
 css-dev: css
@@ -24,4 +28,7 @@ loadplatforms:
 	python src\web\manage.py loaddata platforms.yaml
 
 loadsample:
-	python src\web\manage.py loaddata sample.yaml
\ No newline at end of file
+	python src\web\manage.py loaddata sample.yaml
+
+createsuperuser:
+	python src\web\manage.py createsuperuser
\ No newline at end of file
diff --git a/src/web/tracker/migrations/0002_alter_session_duration_manual.py b/src/web/tracker/migrations/0002_alter_session_duration_manual.py
new file mode 100644
index 0000000..1411fd4
--- /dev/null
+++ b/src/web/tracker/migrations/0002_alter_session_duration_manual.py
@@ -0,0 +1,21 @@
+# Generated by Django 4.1.4 on 2023-01-02 18:55
+
+import datetime
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("tracker", "0001_initial"),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name="session",
+            name="duration_manual",
+            field=models.DurationField(
+                blank=True, default=datetime.timedelta(0), null=True
+            ),
+        ),
+    ]
diff --git a/src/web/tracker/migrations/0003_alter_session_duration_manual_and_more.py b/src/web/tracker/migrations/0003_alter_session_duration_manual_and_more.py
new file mode 100644
index 0000000..8eeb1b1
--- /dev/null
+++ b/src/web/tracker/migrations/0003_alter_session_duration_manual_and_more.py
@@ -0,0 +1,23 @@
+# Generated by Django 4.1.4 on 2023-01-02 23:11
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("tracker", "0002_alter_session_duration_manual"),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name="session",
+            name="duration_manual",
+            field=models.DurationField(blank=True, null=True),
+        ),
+        migrations.AlterField(
+            model_name="session",
+            name="timestamp_end",
+            field=models.DateTimeField(blank=True, null=True),
+        ),
+    ]
diff --git a/src/web/tracker/models.py b/src/web/tracker/models.py
index 8ac5375..30f9811 100644
--- a/src/web/tracker/models.py
+++ b/src/web/tracker/models.py
@@ -31,8 +31,8 @@ class Platform(models.Model):
 class Session(models.Model):
     purchase = models.ForeignKey("Purchase", on_delete=models.CASCADE)
     timestamp_start = models.DateTimeField()
-    timestamp_end = models.DateTimeField()
-    duration_manual = models.DurationField(blank=True, null=True, default=timedelta(0))
+    timestamp_end = models.DateTimeField(blank=True, null=True)
+    duration_manual = models.DurationField(blank=True, null=True)
     duration_calculated = models.DurationField(blank=True, null=True)
     note = models.TextField(blank=True, null=True)