Test project for SparkSQL and ScalaPB.

1. To build:

   $ sbt assembly
   

   Note a line like the follows that provides the path to the JAR we created:

   [info] Packaging /home/.../sparksql-scalapb-test/target/scala-2.12/sparksql-scalapb-test-assembly-0.1.0-SNAPSHOT.jar ...
   

2. Submit the job to your cluster:

   /path/to/spark/bin/spark-submit \
     --jars . \
     --class myexample.RunDemo \
     target/scala-2.12/sparksql-scalapb-test-assembly-0.1-SNAPSHOT.jar