title: Create Postgres database if it doesn't exist when running spring boot application
body: <p>I'm using <code>PostgreSQL</code> and <code>spring-boot-2.0.1</code> and want my app to create the database if it doesn't exist.
  I have the below options in my <code>application.properties</code></p>
  
  <pre><code>spring.jpa.hibernate.ddl-auto=update
  spring.jpa.generate-ddl=true
  spring.jpa.database-platform=org.hibernate.dialect.PostgreSQL94Dialect
  
  spring.datasource.driverClassName=org.postgresql.Driver
  spring.datasource.url=jdbc:postgresql://localhost:5432/mydb
  spring.datasource.username=postgres
  spring.datasource.password=123
  </code></pre>
  
  <p>with the above i'm getting error:</p>
  
  <pre><code>Caused by: org.postgresql.util.PSQLException: FATAL: database "mydb" does not exist
  </code></pre>
  
  <p>any idea what i'm missing?</p>