How to write logfile in csv format using logback?

I have a requirement where I need to write a log in a csv format using logback. I have found a sample where I can do just that

    <appender name="csv" class="ch.qos.logback.core.rolling.RollingFileAppender">
    <file>mylog.csv</file>
    <rollingPolicy class="ch.qos.logback.core.rolling.SizeAndTimeBasedRollingPolicy">
    <!-- rollover daily -->
    <fileNamePattern>mylog-%d{yyyy-MM-dd}.%i.csv</fileNamePattern>
        <!-- each file should be at most 100MB, keep 60 days worth of history, but at most 20GB -->
        <maxFileSize>100MB</maxFileSize>    
        <maxHistory>60</maxHistory>
        <totalSizeCap>20GB</totalSizeCap>
        </rollingPolicy>
       <encoder>
         <pattern>%msg%n</pattern>
        </encoder>
     </appender>

However I also need to have a standard header like this in every file:-

    Time,User,Param1,Param2

How do I add the header in every rolling file