Update Readme

[fabcom-aaron]

I had to spend a couple hours searching through the code to finally get create-issuer to work properly. Adding some documentation about the function and the intro_url config will be helpful for newcomers!

[iugarte1]

Hi @fabcom-aaron,

I'm currently having problems on how to define intro_url. Would you mind to share with me you're cinf.ini file? If not, I would be so pleased if you tell me where did you find the solution.

Thank you

[fabcom-aaron]

If issuer_url=https://issuer.url/issuer
You can just set intro_url=https://issuer.url/issuer/newEndpoint

this inputs an introductionUrl into the issuer.json file.

It is important to recognize that the Blockcerts Mobile app isn't looking for that config when adding an issuer, it is looking for introductionURL( not introductionUrl) so I had to change the issuer.json to match that before the mobile wallet would add the issuer properly.