title: Logback does not write to 3rd party logging service
body: <p>I'm setting up more complex logging then a simple console output. Logback writes logs really well via <code>ConsoleAppender</code>. But when I add extra <code>RollbarAppender</code> it does not work for it.</p>
  
  <p>Here is an example of logback.xml</p>
  
  
  
  <pre><code>&lt;?xml version="1.0" encoding="UTF-8"?&gt;
  &lt;configuration &gt;
      &lt;appender name="CONSOLE" class="ch.qos.logback.core.ConsoleAppender"&gt;
          &lt;encoder&gt;
              &lt;pattern&gt;%highlight([%level]) - [%date] - [%logger]  %msg%n&lt;/pattern&gt;
          &lt;/encoder&gt;
      &lt;/appender&gt;
      &lt;appender name="ROLLBAR" class="com.rollbar.logback.RollbarAppender"&gt;
          &lt;accessToken&gt;VERY_SECRET_TOKEN&lt;/accessToken&gt;
          &lt;encoder&gt;
              &lt;pattern&gt;%highlight([%level]) - [%date] - [%logger]  %msg%n&lt;/pattern&gt;
          &lt;/encoder&gt;
      &lt;/appender&gt;
  
      &lt;logger name="akka" level="ERROR" additivity="false"&gt;
          &lt;appender-ref ref="ROLLBAR" /&gt;
      &lt;/logger&gt;
      &lt;logger name="slick" level="ERROR"/&gt;
  
      &lt;root level="INFO"&gt;
          &lt;appender-ref ref="CONSOLE" /&gt;
      &lt;/root&gt;
  
  &lt;/configuration&gt;
  </code></pre>
  
  <p>Meanwhile this configuration works fine and sends logs to the 3rd party logging service, but doesn't write to the console :(</p>
  
  
  
  <pre><code>&lt;?xml version="1.0" encoding="UTF-8"?&gt;
  &lt;configuration &gt;
      &lt;appender name="CONSOLE" class="ch.qos.logback.core.ConsoleAppender"&gt;
          &lt;encoder&gt;
              &lt;pattern&gt;%highlight([%level]) - [%date] - [%logger]  %msg%n&lt;/pattern&gt;
          &lt;/encoder&gt;
      &lt;/appender&gt;
      &lt;appender name="ROLLBAR" class="com.rollbar.logback.RollbarAppender"&gt;
          &lt;accessToken&gt;VERY_SECRET_TOKEN&lt;/accessToken&gt;
          &lt;encoder&gt;
              &lt;pattern&gt;%highlight([%level]) - [%date] - [%logger]  %msg%n&lt;/pattern&gt;
          &lt;/encoder&gt;
      &lt;/appender&gt;
  
      &lt;logger name="akka" level="INFO" additivity="false"&gt;
          &lt;appender-ref ref="CONSOLE" /&gt;
      &lt;/logger&gt;
      &lt;logger name="slick" level="ERROR"/&gt;
  
      &lt;root level="ERROR"&gt;
          &lt;appender-ref ref="ROLLBAR" /&gt;
      &lt;/root&gt;
  
  &lt;/configuration&gt;
  </code></pre>
  
  <p>So I'm confused. How to make logback work in this way:</p>
  
  <p>INFO level events write to the console</p>
  
  <p>ERROR level events write to the console + ROLLBAR</p>