Support sample table data in DBML

[hdnax]

Summary

• Support sample table data in DBML

Table Users {
  id string [pk]
  name string
  age int
  
  Records { // implicit columns
    "id1", "name", 18
    "id2", "name", "19"
  }
	
  Records (id, name) { // explicit columns
  }
}

Records Users(id, name) { // always explicit
}

• Handle INSERT statements in importers and exporters.

Issue

(issue link here)

Lasting Changes (Technical)

(please list down: code changes/things that have wide-effect; new libraries/functions added that can be used by others; examples below)

• (Added class EmailValidator to validate email address' validity)
• (Added Tenant#is_trial? check)

Checklist

Please check directly on the box once each of these are done

• Documentation (if necessary)
• Lint Checks Passed
• Unit Tests Passed
• Coverage Tests Passed
• Integration Tests Passed
• Code Review