Improve demo documentation

dbt-demo/src/ratpack/Ratpack.groovy

@@ -1,42 +1,67 @@
 import com.devsoap.dbt.DBTModule
-import com.devsoap.dbt.config.DBTConfig
-import com.devsoap.dbt.demo.DatabaseService
 import com.devsoap.dbt.services.TransactionManagerService
+import org.flywaydb.core.Flyway
 import org.h2.jdbcx.JdbcDataSource
 import ratpack.form.Form
 import ratpack.handlebars.HandlebarsModule
 import ratpack.http.Status
+import ratpack.service.Service
 
 import javax.sql.DataSource
 
 import static ratpack.groovy.Groovy.ratpack
 import static ratpack.handlebars.Template.handlebarsTemplate
 
+/*
+ * Ratpack main configuration
+ */
 ratpack {
 
-  serverConfig {
-    sysProps()
-    require('/dbt', DBTConfig)
-  }
-
+  /*
+   * Configure application bindings
+   */
   bindings {
+
+    /*
+     * Render views with Handlebars
+     */
     module HandlebarsModule
 
-    module (DBTModule) {
-      it.ledger.remoteUrl = 'http://localhost:5050/ledger'
-      it.executor.remoteUrl = 'http://localhost:5050/executor'
+    /*
+     *  Configure dbt module to point to correct ledger and executor instances
+     */
+    module (DBTModule) { config ->
+      config.ledger.remoteUrl = 'http://localhost:5050/ledger'
+      config.executor.remoteUrl = 'http://localhost:5050/executor'
     }
 
+    /*
+     * Configure data source to use H2 in-memory database
+     */
     bindInstance(DataSource, new JdbcDataSource(url: 'jdbc:h2:mem:dbtdb;DB_CLOSE_DELAY=-1', user: ''))
-    bind DatabaseService
+
+    /*
+     * Migrate Flyway migrations at application start
+     */
+    bindInstance { event -> new Flyway(dataSource: event.registry.get(DataSource)).migrate() } as Service
   }
 
+
+  /*
+   * Configure API endpoints
+   */
   handlers {
 
+    /*
+     * Render index.html at root url
+     */
     get {
       render handlebarsTemplate('index.html')
     }
 
+    /*
+     * Adds a new query to the current transaction
+     */
     post('addQueryToTransaction') {
       def transactionManager = get(TransactionManagerService)
       parse(Form).then { Form form ->
@@ -58,6 +83,9 @@ ratpack {
       }
     }
 
+    /*
+     * Executes the current transaction by marking the transaction as complete and executing the transaction
+     */
     post('executeTransaction') {
       def transactionManager = get(TransactionManagerService)
       parse(Form).then { Form form ->
@@ -73,6 +101,9 @@ ratpack {
       }
     }
 
+    /*
+     * Adds the query to a new transaction and executes the transaction immediately
+     */
     post('executeQuery') {
       def transactionManager = get(TransactionManagerService)
       parse(Form).then { Form form ->