Maven: Including a META-INF folder in the classes folder

I have a very simple WAR project and I want to include a directory named META-INF at the top of the classes output folder where all the compiled Java classes are. I'm using Maven, but it seems that by default Maven won't include anything that is not a Java class. So it ignores my META-INF directory that is sitting at the top of the src directory. The META-INF directory contains a file named persistence.xml. Any quick pointers on how to instruct Maven to put this directory and file into the output folder?