title: How to find postgresql uri for SQLALCHEMY config
body: <p>I am trying to connect my flask app to my prostgreSQL db, and i find this configuration example (below code). I just do not know how to find my postgreSQL URI</p>
  
  <pre><code>app = Flask(__name__)
  #how do i know my postgresql URI
  app.config['SQLALCHEMY_DATABASE_URI'] = 'postgresql://localhost/pre-registration'
  db = SQLAlchemy(app)
  </code></pre>