title: Class not found on sbt build
body: <p>I'm getting the following error on my sbt build. I'm trying to configure logentries logging on my Scala project. I have added all the required dependencies but I'm still getting the following errors </p>
  
  <blockquote>
    <p>ch.qos.logback.core.util.DynamicClassLoadingException: Failed to
    instantiate type com.logentries.log4j.LogentriesAppender</p>
  </blockquote>
  
  <pre><code>Caused by: java.lang.NoClassDefFoundError: org/apache/log4j/AppenderSkeleton
  </code></pre>
  
  <p>Any suggestions?</p>
  
  <p>My list of dependencies is </p>
  
  <pre><code> libraryDependencies ++= Seq(
        "net.coobird" % "thumbnailator" % "0.4.8",
        "org.julienrf" %% "play-json-variants" % "2.0",
        "org.elasticsearch" % "elasticsearch" % "2.4.1",
        "org.elasticsearch.module" % "lang-groovy" % "2.4.1" % "test",
        "com.datastax.cassandra" % "cassandra-driver-core" % "2.1.10.3" exclude("com.codahale.metrics", "metrics-core"),
        "org.twitter4j" % "twitter4j-core" % "4.0.2",
        "com.stripe" % "stripe-java" % "3.3.0",
        "org.quartz-scheduler" % "quartz" % "2.2.1",
        "com.ecwid" % "ecwid-mailchimp" % "2.0.1.0" exclude("commons-logging", "commons-logging"),
        "org.ocpsoft.prettytime" % "prettytime" % "3.2.7.Final",
        "org.isomorphism" % "token-bucket" % "1.3",
        "io.dropwizard.metrics" % "metrics-core" % "3.1.2",
        "com.typesafe.play" %% "anorm" % "2.5.1",
        "com.connectifier.xero" % "client" % "0.13",
        "io.intercom" % "intercom-java" % "2.2.1",
        "org.scala-lang.modules" % "scala-java8-compat_2.11" % "0.7.0",
        "org.asynchttpclient" % "async-http-client" % "2.0.0",
        "org.mockito" % "mockito-core" % "1.10.19",
        "org.powermock" % "powermock-mockito-release-full" % "1.6.4",
        "com.google.code.findbugs" % "jsr305" % "3.0.2" % "compile",
        "com.cebglobal" % "xpresso" % "0.9.0",
        "com.sksamuel.scrimage" %% "scrimage-core" % "2.1.7",
        "com.googlecode.htmlcompressor" % "htmlcompressor" % "1.5.2",
        "org.lyranthe.prometheus" %% "play25" % "0.8.4",
        "com.sksamuel.elastic4s" % "elastic4s-core_2.11" % "2.4.0" exclude("com.fasterxml.jackson.core", "jackson-core"),
        "com.sksamuel.elastic4s" %% "elastic4s-streams" % "2.4.0",
        "com.typesafe.akka" %% "akka-stream" % "2.4.18",
        "ch.qos.logback" % "logback-classic" % "1.0.11",
        "org.jsoup" % "jsoup" % "1.9.1",
        "com.amazonaws" % "aws-java-sdk" % "1.11.214",
        "com.amazonaws" % "aws-java-sdk-api-gateway" % "1.11.230",
        "com.github.tototoshi" %% "scala-csv" % "1.3.5",
        "com.logentries" % "logentries-appender" % "1.1.38",
        "org.slf4j" % "slf4j-api" % "1.7.25"
      ),
  </code></pre>