Improve README

[andrealmar]

Hi my friend,

Thanks for your repo. I want to suggest an improvement in README. For example:

I've set up a Discord server. Where do I have to install your npm package? I've created a server on Google Cloud just to run your npm package. If I go with npm install jira-webhook-discord it doesn't work. I had to git clone YOUR_JIRA_WEBHOOK_REPO to my Google Cloud server and install the http-errors package. After that I was able to npm start.

My Google Server is running now what? I've configured a Webhook in JIRA pointing to the Webhook URL that Discord gave me: https://discordapp.com/api/webhooks/WEBHOOK_ID/WEBHOOK_TOKEN

But when I create a new issue on a project on JIRA it doesn't show on my Discord channel. What am I doing wrong?

I appreciate any help. Thanks!!!