In PiranhaCMS we use the standard TinyMCE but would like to add the ImageCaption functionality from TinyMCE

This is how the documentation does it, but how would one add the image_caption functionality in Piranha?

  selector: 'textarea',  
  plugins: 'image',
  menubar: 'insert',
  toolbar: 'image',
  image_caption: true

I’m aware that it should be done in Piranha.Manager.Editor.EditorConfig.Current in Configure but I find no examples on how actually add this config to the EditorConfig.