Can we add reactions to slack messages when an issue is transitioned using Webhooks?

[Panagiotis]

Hello,

I would like to ask if it is possible to add a reaction to slack messages every time an issue is transitioned. 

From the Jira side, we are going to create a webhook to post the information on a system that's running the script to add the reaction on slack and I have two questions about this,

1. When it comes to "Issue Related Events", is "updated" the correct option?
2. If we want this to be triggered only on a specific transition, besides adding the webhook to the specific transition, do I need to do something else? 

Thank you in advance.