title: No suitable driver found for jdbc:postgresql when trying to connect spark-shell (inside a docker container) to my PostgreSQL database
body: <p>I'm running Spark on a docker container (<a href="https://github.com/sequenceiq/docker-spark" rel="nofollow">sequenceiq/spark</a>).<br>
  I launched it like this: </p>
  
  <pre><code>docker run --link dbHost:dbHost  -v my/path/to/postgres/jar:postgres/ -it -h sandbox sequenceiq/spark:1.6.0 bash
  </code></pre>
  
  <p>I'm sure that the postgreSQL database is accessible through the address <code>postgresql://user:password@localhost:5432/ticketapp</code>.</p>
  
  <p>I start the spark-shell with <code>spark-shell --jars postgres/postgresql-9.4-1205.jdbc42.jar</code> and since I can connect from my Play! application that has as dependency <code>"org.postgresql" % "postgresql" % "9.4-1205-jdbc42"</code> it seems that I have the correct jar. (I also don't any warning saying that the local jar does not exist.) </p>
  
  <p>But when I try to connect to my database with: </p>
  
  <pre><code>val jdbcDF = sqlContext.read.format("jdbc").options(
    Map("url" -&gt; "jdbc:postgresql://dbHost:5432/ticketapp?user=user&amp;password=password", 
      "dbtable" -&gt; "events")
    ).load()
  </code></pre>
  
  <p>(I also tried the url <code>jdbc:postgresql://user:root@dbHost:5432/ticketapp</code>)</p>
  
  <p>as it is explained in the spark documentation, I get this error: 
  java.sql.SQLException: No suitable driver found for jdbc:postgresql://dbHost:5432/ticketapp?user=simon&amp;password=root</p>
  
  <p>What am I doing wrong?</p>