That seems to be good

src/backend/main/admin.py

@@ -4,6 +4,14 @@
 from . import models
 
 
+class TrackItemInline(admin.TabularInline):
+    model = models.TrackItem
+
+
+class LogItemInline(admin.TabularInline):
+    model = models.UserLog
+
+
 @admin.register(models.User)
 class MainUserAdmin(UserAdmin):
     fieldsets = (
@@ -21,8 +29,30 @@ class MainUserAdmin(UserAdmin):
             'fields': ('email', 'password1', 'password2'),
         }),
     )
-    list_display = ('email', 'first_name', 'last_name', 'is_staff')
+    list_display = ('email', 'first_name', 'last_name', 'age', 'is_staff')
     list_filter = ('is_staff', 'is_superuser', 'is_active', 'groups')
     search_fields = ('first_name', 'last_name', 'email')
-    ordering = ('email',)
+    ordering = ('id',)
     filter_horizontal = ('groups', 'user_permissions',)
+    inlines = [
+        TrackItemInline,
+    ]
+
+
+@admin.register(models.PortionItem)
+class BasicModelAdmin(admin.ModelAdmin):
+    list_display = ('name', 'is_default')
+    list_filter = ('is_default',)
+    search_fields = ('name',)
+    ordering = ('id',)
+
+
+@admin.register(models.TrackItem)
+class TrackItemAdmin(admin.ModelAdmin):
+    list_display = ('item', 'user', 'target', 'order', 'frequency')
+    list_filter = ('target',)
+    search_fields = ('item__name', 'user__email', 'user__first_name', 'user__last_name')
+    ordering = ('id',)
+    inlines = [
+        LogItemInline,
+    ]

src/backend/main/migrations/0002_portionitem_trackitem_userlog.py

@@ -0,0 +1,53 @@
+# Generated by Django 3.2.8 on 2021-11-09 19:07
+
+from django.conf import settings
+from django.db import migrations, models
+import django.db.models.deletion
+import django.utils.timezone
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('main', '0001_initial'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='PortionItem',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('name', models.CharField(max_length=150, verbose_name='item name')),
+                ('is_default', models.BooleanField(default=False, verbose_name='is default?')),
+            ],
+            options={
+                'verbose_name': 'portion item',
+                'verbose_name_plural': 'portion items',
+            },
+        ),
+        migrations.CreateModel(
+            name='TrackItem',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('target', models.IntegerField(default=1, verbose_name='target')),
+                ('order', models.IntegerField(blank=True, null=True, verbose_name='order')),
+                ('frequency', models.IntegerField(default=1, verbose_name='frequency')),
+                ('item', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='main.portionitem')),
+                ('user', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to=settings.AUTH_USER_MODEL)),
+            ],
+            options={
+                'ordering': ['order'],
+            },
+        ),
+        migrations.CreateModel(
+            name='UserLog',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('timestamp', models.DateTimeField(default=django.utils.timezone.now, verbose_name='timestamp')),
+                ('item', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='main.trackitem')),
+            ],
+            options={
+                'ordering': ['timestamp'],
+            },
+        ),
+    ]

src/backend/main/models.py

@@ -191,24 +191,24 @@ class TrackItem(models.Model):
     user = models.ForeignKey(User, on_delete=models.CASCADE)
     target = models.IntegerField(_('target'), default=1)
     order = models.IntegerField(_('order'), **NULL_BLANK)
-    frequency = models.IntegerChoices(_('frequency'), default=Frequency.DAILY)
+    frequency = models.IntegerField(_('frequency'), default=Frequency.DAILY)
 
     class Meta:
         ordering = ['order']
 
     def __str__(self):
-        return super().__str__()
+        return f'TrackItem({self.user} - {self.item})'
 
 
 class UserLog(models.Model):
     """
     A class representing a log.
     """
-    item = models.ForeignKey(TrackItem)
-    timestamp = models.DateTimeField()
+    item = models.ForeignKey(TrackItem, on_delete=models.CASCADE)
+    timestamp = models.DateTimeField(_('timestamp'), default=timezone.now)
 
     class Meta:
         ordering = ['timestamp']
 
     def __str__(self):
-        return super().__str__()
+        return f'UserLog({self.item} - {self.timestamp})'