I need COUNT to return 0

Question

I have two tables with the following data:

I want to rescue from the database all users and the amount of jobs they have performed. I was using the following SQL:

SELECT u.usuario, COUNT(t.id) AS '4' 
FROM usuario u LEFT JOIN trabalho t 
ON u.usuario = t.idUsuario 
WHERE t.realizado = 1 
AND t.dataTermino <= '2018-05-01' 
AND t.dataTermino >= '2018-04-01' 
GROUP BY u.usuario 

The problem is that if there is no work done for a user, the line is not returned, and I want to return the user name and 0.