Add inline model to django admin site

Question

I have this two models:

class Rule(models.Model):
    name = models.CharField(max_length=200)

class Channel(models.Model):

    id = models.CharField(max_length=9, primary_key=True)
    name = models.CharField(max_length=100)
    rule = models.ForeignKey(Rule, related_name='channels', blank=True)

And I have to be able to add channels to rule in admin site within RuleAdmin interface. So I created this two admin models:

class ChannelAdmin(admin.TabularInline):
    model = Channel

class RuleAdmin(admin.ModelAdmin):
    model = Rule
    inlines = [ChannelAdmin]

But when I start my server I got this errors:

ERRORS:
<class 'main.admin.ChannelAdmin'>: (admin.E202) 'main.Channel' has no ForeignKey to 'main.Channel'.

Still in django shell I can make queries like

rule = Rule.objects.get(pk=1)
rule.channels.all()

There is gotta be something obvious but I just can't figure it out.

Answer 1

do something like this:

class ChannelAdmin(admin.TabularInline):
    model = Channel

class RuleAdmin(admin.ModelAdmin):
   inlines = [ChannelAdmin,]

admin.site.register(Rule,RuleAdmin)

Answer 2

class OrderItemInline(admin.TabularInline):
    model = OrderItem
    fields = ['image']    

class OrderAdmin(admin.ModelAdmin):
    list_display = ['id']
    list_filter = ['status']
    inlines = [OrderItemInline]