Fix the reference to the "Dockerfiles" section

website/source/docs/builders/docker.html.md

@@ -21,7 +21,7 @@ Dockerfiles, Packer is able to provision containers with portable scripts or
 configuration management systems that are not tied to Docker in any way. It also
 has a simpler mental model: you provision containers much the same way you
 provision a normal virtualized or dedicated server. For more information, read
-the section on [Dockerfiles](#toc_8).
+the section on [Dockerfiles](#dockerfiles).
 
 The Docker builder must run on a machine that has Docker installed. Therefore
 the builder only works on machines that support Docker (modern Linux machines).
@@ -275,6 +275,8 @@ shown below:
 
 [Learn how to set Amazon AWS credentials.](/docs/builders/amazon.html#specifying-amazon-credentials)
 
+<span id="dockerfiles"></span>
+
 ## Dockerfiles
 
 This builder allows you to build Docker images *without* Dockerfiles.