title: TRIGGER SALESFORCE/APEX
body: <p>I have to complete a challenge and i have no idea where to starts it.</p>
  <p>I created the object &quot;customer&quot;, with the fields: name, birth date, age, and account (lookp up to account)</p>
  <p>1- Dont allow insert record if the birth date is empty, and shows an error message to the user.
  2-dont allow to create a record of customer with age less than 18, and shows an error message to the user.
  3-if the field account is empty shoud create automatically an account and insert on the field.
  4-when a record is created a new opportunity should be create and the field customer should be filled.</p>
  <p>Can someone help me with that?</p>