Have you tried logging in from a shell with those credentials?
Did you really intend to use peer auth on your system? Postgres
offers a variety of authentication schemes; "trust" might be more
appropriate for dev work, but up to you.
In terminal I have created a role user and password what I have given in database.yml file by this command below and I solved the problem. Thanks for your reply.
psql -U postgres ------ run console
CREATE ROLE XXXX WITH LOGIN SUPERUSER PASSWORD ‘XXXXX’; ------- to create a role