Simplified Version of PR 99, Version 3 to Verison 4

[salgsstyrke]

@rosalindlopez wrote a really awesome solution for transitioning from the current V3 of the app to this new V4. But it requires people to already be familiar with CCI, devops, etc.

To simplify it we can:
look at this commit to PR 99. 814fe30#diff-abc0dc21f2901fb2b631a5520473e8d745c6a564ee4566106dec712b8ff52396

1. create this field on the Unsubscribe object.

Migrated_Record_Id__c false If this record was migrated from the older Salesforce Labs application, the 18 digit Id of the original record will be stored here. Migrated Record Id 18 false false Text false

2. Create instructions for users to themselves create the flow that is included in this commit. It basically calls an apex action, as far as I understand.
3. Write instructions for how to copy and paste in the apex code from the same commit. That's an apex class and a test class.
4. Try this out in an org that has both version 3 and version 4 installed.

[salgsstyrke]

@DKeatonDC I added this new issue that could be worked on. Thanks for leading the sprint!

[klebell-GSN]

will tackle this tomorrow - writing up instructions for:

• adding new Migrated Record ID
• creating new apex classes (copy and paste code)
• create flow that calls apex action