I usually use a field under the ‘user’ data type called ‘userType’
This can be a text value or you can use an option set for this value.
In your case, thise value will either be ‘employee’ or ‘employer’.
So, when a user logs in, your workflows and UI can be designed to work in a conditional manner depending on the ‘userType’ value of the current User.
The Database will remain the same.
You can have 2 additional data types:
Employer Info
Employee Info
Your User data type can contain both these fields and when the user signs up, you can create a new thing of the corresponding data type and assign it to the user.
So, for example if a User signs up as an employee, your signup workflow will also create a new thing of type ‘Employee Info’, add all the employee info provided during signup into that thing and assign it to the ‘EmployeeInfo’ field of the Current User. In this case, the current user’s Employer Info field will remain empty.
Then you can have another data type called ‘Jobs’ that only Employers can create and display these in a repeating group on your ‘Job Listings’ page.