title: Intellij Idea can't find jar file
body: <p>I've been trying to import Apache Commons Math into a Scala program in IntelliJ IDEA. I've identified the jar in the file system via project structure dialog. Using the 'jar -tf ' command on the jar file, I see the classes are all there. In the Scala source code I have 'import org.apache.commons.math3._' and yet somehow IntelliJ cannot find the library. What am I missing?</p>