Release 2.1

Changes

• Refactored the current unit tests [#4]
• Created unit testing logic for the GetEmployees_WhenCalled_ShouldReturnIEnumerableOfEmployeeDto() method [#5]
• Created a new folder called Tests which is to store the unit and integration tests [#6]
• Created integration tests for the EmployeeRepository class [#9]
• Removed the RP.Domain layer and added the models inside the RP.Data layer instead [#11]
• Changed the application version to 2.1 [#13]
• Created an RP.CompositionRoot layer which contains the dependency injection registrations [#20]