Add instructions to setup PostgreSQL

data/guides.yml

@@ -52,6 +52,7 @@ categories:
   - path: models
     pages:
       - path: overview
+      - path: database-configuration
       - path: repositories
       - path: entities
       - path: data-types

source/guides/models/database-configuration.md

@@ -0,0 +1,41 @@
+---
+title: Guides - Database Configuration
+---
+
+# Database Configuration
+
+Before starting your server, you need to configure the database link in <code>.env*</code> files.
+
+Open this file for each environment and update <code>DATABASE_URL</code> for your database.
+
+## <a href="http://www.postgresql.org/" target="_blank">PostgreSQL</a>
+
+Setup database variable for the development environment:
+
+```
+# .env.development
+DATABASE_URL="postgresql://username:password@localhost/bookshelf_development"
+```
+
+Setup database variable for the test environment:
+
+```
+# .env.test
+DATABASE_URL="postgresql://username:password@localhost/bookshelf_test"
+```
+
+# Setup your database
+
+After your database variables setup is done you need to create the database and run the migrations before being able to launch a development server.
+
+In your terminal, enter:
+
+```
+% bundle exec hanami db prepare
+```
+
+To setup your test environment database, enter:
+
+```
+% HANAMI_ENV=test bundle exec hanami db prepare
+```