Destroy associated rules when a channel is destroyed

app/models/channel.rb

@@ -10,6 +10,11 @@ class DiscourseChat::Channel < DiscourseChat::PluginModel
     self.data = {} if self.data.nil?
   end
 
+  after_destroy :destroy_rules
+  def destroy_rules
+    rules.destroy_all()
+  end
+
   validate :provider_valid?, :data_valid?
 
   def provider_valid?

spec/models/channel_spec.rb

@@ -52,6 +52,17 @@ RSpec.describe DiscourseChat::Channel do
     expect(channel.rules.size).to eq(2)
   end
 
+  it 'destroys its rules on destroy' do
+    channel = DiscourseChat::Channel.create({provider:'dummy'})
+    expect(channel.rules.size).to eq(0)
+    rule1 = DiscourseChat::Rule.create(channel: channel)
+    rule2 = DiscourseChat::Rule.create(channel: channel)
+
+    expect(DiscourseChat::Rule.with_channel(channel).exists?).to eq(true)
+    channel.destroy()
+    expect(DiscourseChat::Rule.with_channel(channel).exists?).to eq(false)
+  end
+
   describe 'validations' do
     let(:channel) {  }