Hello good people!
We have a project, and we need to make an external web page with an anonymous form that connects to a Custom object in Salesforce. At the moment our top option is Heroku, but we are still not sure how the system works(Exactly how to develop the app and deploy it). Any suggestions from experienced people? 
Thank you in advance

Hi 
I am working on Trailhead module: Test your Process. I followed all the steps in creating Process Builder through Trailhead and I am getting below error:
Challenge Not yet complete... here's what's wrong: 
There was an unexpected error in your org which is preventing this assessment check from completing: System.DmlException: Insert failed. First exception on row 0; first error: FIELD_CUSTOM_VALIDATION_EXCEPTION, Account number must be 8 characters long: []
Can one of you help or let me know, what I am doing wrong.
Thanks