Install TaskListener into docker image

Hi,

Warning: I’m new to camunda and not a java developer.

I have written my own task listener and packaged it in a jar using maven. I am hosting camunda using docker (camunda/camunda-bpm-platform:7.12.0-SNAPSHOT) and want to install my task listener into the container. I have tried copying the task listener jar to /camunda/lib in the docker image but i still get this when i try to start my process which references the task listener:
camunda_1 | Caused by: org.camunda.bpm.engine.ProcessEngineException: ENGINE-03051 There was an exception while invoking the TaskListener. Message: ‘ENGINE-09008 Exception while instantiating class ‘com.fte.camunda.TestTaskListener’: ENGINE-09017 Cannot load class ‘com.fte.camunda.TestTaskListener’: com.fte.camunda.TestTaskListener’
camunda_1 | at org.camunda.bpm.engine.impl.db.EnginePersistenceLogger.invokeTaskListenerException(EnginePersistenceLogger.java:449)

Ultimately i want to hook my own task engine into camunda (https://camunda.com/best-practices/integrating-a-third-party-tasklist/#__strong_creating_strong_tasks) and apply this globally using camunda-bpm-reactor or by using the parser approach.

Do i need to register my task listener in a config file somewhere?

Thanks