title: Creating User For Postgresql
body: <p>When I enter <code>su postgres</code> it is asking for a password and I did not set any prior password. 
  I am using a Django book and have installed PostgreSQL with <code>sudo apt-get install PostgreSQL PostgreSQL-contrib</code> I installed it within a virtual environment the instructions are vague on where to install so I just install it in there. Also installed the install the <strong>psycopg2 PostgreSQL adapter for Python</strong> with 
  <code>pip install psycopg2-binary==2.8.4</code>. I am now in the next step to create a user for the <strong>PostgreSQL</strong> but can't pass that step the instructions provided are to enter <code>su postgres</code> and immediately after <code>createuser -dp user-name</code> and it is asking for a password. I have entered my superuser password but showing authentication failure. 
  Thanks </p>