title: Configuring Serilog to write to Slack via app.config
body: <p>I've created an application that I want to get logging to Slack for a particular purpose. I've already confirmed that it is working logging to a RollingFile and to Seq. I've added in serilog.sinks.slackclient and the application runs, and logs, but nothing shows up in my Slack channel.</p>
  
  <p>Can someone verify whether there is an issue with my config?</p>
  
  <p>from app.config (obviously xxx, yyy, zzz are substituded for key values.):</p>
  
  <pre><code>&lt;add key="serilog:minimum-level" value="Debug" /&gt;
  &lt;!--&lt;add key="serilog:using:RollingFile" value="Serilog.Sinks.RollingFile" /&gt;--&gt;
  &lt;add key="serilog:using:Slack" value="Serilog.Sinks.Slack" /&gt;
  &lt;add key="serilog:write-to:Slack" value="https://hooks.slack.com/services/xxx/yyy/zzz" /&gt;
  &lt;add key="serilog:write-to:Seq.serverUrl" value="http://localhost:5341/" /&gt;
  &lt;add key="serilog:write-to:RollingFile.pathFormat" value="C:\Logs\Serilog\Test-{Date}.txt" /&gt;
  &lt;add key="serilog:write-to:RollingFile.retainedFileCountLimit" value="10" /&gt;
  </code></pre>