slick 3.1.1 provisioning error in the configuration how can I get this working

[hernand...@gmail.com]

I am new to slick and am using version 3.1.1 along with the playframework 2.4.6 . I am following this guide in the documentation http://slick.typesafe.com/doc/3.1.1/database.html . The error I am getting is

    ***ProvisionException: Unable to provision, see the following errors:


    1) Error injecting constructor, java.lang.RuntimeException: java.lang.ClassNotFoundException:
    org.postgresql.ds.PGSimpleDataSource
      at controllers.Application.<init>(Application.scala:12)
      while locating controllers.Application
        for parameter 1 at router.Routes.<init>(Routes.scala:31)
      while locating router.Routes
      while locating play.api.inject.RoutesProvider
      while locating play.api.routing.Router
    1 error***

This is what I have first in the SBT I put this

    libraryDependencies ++= Seq(
      "com.typesafe.slick" %% "slick" % "3.1.1",
      "org.slf4j" % "slf4j-nop" % "1.6.4"
    )

Then in my Application.Conf I put this

    mydb = {
      dataSourceClass = org.postgresql.ds.PGSimpleDataSource
      properties = {
        databaseName = "mydatabasename"
        user = "postgres"
        password = "mypassword"
      }
      numThreads = 10
    }

Then finally in my controller I just have the connection string

package controllers 

   import javax.sql.DataSource
   
    import org.mindrot.jbcrypt.BCrypt
    import play.api._
    import play.api.mvc._
    import slick.driver.PostgresDriver.api._
    import scala.concurrent.ExecutionContext.Implicits.global
   
   
    class Application extends Controller {


      val db = Database.forConfig("mydb")
      try {
        // ...
      } finally db.close()
   
   




      def index = Action {


        Ok("My First Controller")
      }
   
    }

The error seems to be coming from  val db = Database.forConfig("mydb")

As you can see I put the postgres driver instead of the H2 since I'm working with postgres and those credentials are the correct ones and verified.

        databaseName = "mydatabasename"
        user = "postgres"
        password = "mypassword"