# Functions
NewAddUserInteractor creates a new instance witch implements AddUserUseCase.
NewGetAllUsersInteractor creates a new instance witch implements GetAllUsersUseCase.
NewGetUserByUsernameInteractor creates a new instance witch implements GetUserByUsernameUseCase.
NewUpdateUserInteractor creates a new instance witch implements UpdateUserUseCase.
# Structs
AddUserCommand is the command to add a new user.
GetAllUsersQuery is the query to get all users from the data store.
GetUserByUsernameQuery is the query for getting a user by username.
UpdateUserCommand is the command for updating a user.
UsernameExistsQuery is the query to check if the username exists.
# Interfaces
AddNewUserGateway is the data store gateway to add a new user.
AddUserUseCase is the use case to add a new user.
DoesUsernameExistsGateway is the data store gateway to check if the username exists.
GetAllUsersGateway is the data store gateway to get all users.
GetAllUsersUseCase is the use case to get all users from the data store.
GetUserByUsernameGateway is the data store gateway for getting a user by username.
GetUserByUsernameUseCase is the use case for getting a user by username.
UpdateUserGateway is the data store gateway for updating a user.
UpdateUserUseCase is the use case for updating a user.