Ckeditor auto add class to p - ckeditor

Question

I would like to add class "text-justify" automatically to every p, anyone know how to do this?
Now I am using this code:
CKEDITOR.on('dialogDefinition', function (ev) {
var dialogName = ev.data.name;
var dialogDefinition = ev.data.definition;
if (dialogName == 'table' || dialogName == 'tableProperties') {
var info = dialogDefinition.getContents('info');
// Remove fields
var cellSpacing = info.remove('txtCellSpace');
var cellPadding = info.remove('txtCellPad');
var border = info.remove('txtBorder');
var width = info.remove('txtWidth');
var height = info.remove('txtHeight');
var align = info.remove('cmbAlign');
}
});
$('#content, #longContent').ckeditor({
contentsCss: '/CMS/style_ckeditor.css',
allowedContent: true,
extraPlugins: 'button,menubutton,htmlbuttons,menu,floatpanel,panel',
htmlbuttons: [
{
name:'button1',
icon:'icon1.png',
html:'<p class="act-left">Sekretarz Zgromaczenia<br /><strong>Alfred Błaszczyk</strong></p><p class="act-right">Przewodniczący Zgromadzenia<br /><strong>Tomasz Radomski</strong></p><div class="clearfix"></div>',
title:'Dodaj podpisy'
},
{
name:'button2',
icon:'icon3.png',
html:'<ol class="law"><li> <ol><li>tekst</li></ol></li></ol>',
title:'Dodaj paragraf'
}
]
}).ckeditorGet().on('insertElement', function (event) {
var el = event.data;
if (el.is('table')) {
$(event.data.$)
.addClass('table table-bordered table-striped')
.removeAttr('cellpadding cellspacing')
.wrap('<div class="table-responsive"></div>');
}
}, null, null, 20);
It works for adding classes for table, but when I would like to do similar to P, it didn't work.

Answer 1

just use :
$('#content').ckeditor({
on: {
instanceReady: function () {
this.dataProcessor.htmlFilter.addRules({
elements: {
ul: function (el) {
el.addClass('ul');
},
table: function (el) {
el.addClass('entry');
}
}
});
}
}
});
For Ckeditor4