diff --git a/config/initializers/mixins.rb b/config/initializers/mixins.rb
new file mode 100644
index 00000000..ca527e2d
--- /dev/null
+++ b/config/initializers/mixins.rb
@@ -0,0 +1 @@
+Docker::Container::send(:include, DockerContainerMixin)
diff --git a/lib/docker_client.rb b/lib/docker_client.rb
index 00fd8872..c3a87c51 100644
--- a/lib/docker_client.rb
+++ b/lib/docker_client.rb
@@ -62,11 +62,9 @@ class DockerClient
 
   def self.destroy_container(container)
     container.stop.kill
-    if container.json['HostConfig']['PortBindings']
-      container.json['HostConfig']['PortBindings'].values.each do |configuration|
-        port = configuration.first['HostPort'].to_i
-        PortPool.release(port)
-      end
+    (container.port_bindings.try(:values) || []).each do |configuration|
+      port = configuration.first['HostPort'].to_i
+      PortPool.release(port)
     end
     container.delete(force: true)
   end
diff --git a/lib/docker_container_mixin.rb b/lib/docker_container_mixin.rb
new file mode 100644
index 00000000..0563831f
--- /dev/null
+++ b/lib/docker_container_mixin.rb
@@ -0,0 +1,9 @@
+module DockerContainerMixin
+  def binds
+    json['HostConfig']['Binds']
+  end
+
+  def port_bindings
+    json['HostConfig']['PortBindings']
+  end
+end
diff --git a/spec/lib/docker_container_mixin_spec.rb b/spec/lib/docker_container_mixin_spec.rb
new file mode 100644
index 00000000..24e45be9
--- /dev/null
+++ b/spec/lib/docker_container_mixin_spec.rb
@@ -0,0 +1,11 @@
+require 'rails_helper'
+
+describe DockerContainerMixin do
+  [:binds, :port_bindings].each do |method|
+    describe "##{method}" do
+      it 'is defined for Docker::Container' do
+        expect(Docker::Container.instance_methods).to include(method)
+      end
+    end
+  end
+end