Database migration handled by Flyway, SQL scripts updated

core-api/src/main/java/org/openhubframework/openhub/api/entity/MutableNode.java

@@ -29,7 +29,8 @@ public class MutableNode extends AbstractNode {
      */
     @Id
     @Column(name = "node_id")
-    @GeneratedValue(strategy = GenerationType.AUTO)
+    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "openhub_node_id_sequence")
+    @SequenceGenerator(name="openhub_node_id_sequence", sequenceName="openhub_node_sequence", allocationSize=1)
     private Long nodeId;
 
     /**

core/pom.xml

@@ -81,6 +81,10 @@
             <groupId>org.springframework</groupId>
             <artifactId>spring-jdbc</artifactId>
         </dependency>
+        <dependency>
+            <groupId>org.flywaydb</groupId>
+            <artifactId>flyway-core</artifactId>
+        </dependency>
 
         <!-- misc -->
         <dependency>

core/src/main/resources/db/README.md

@@ -0,0 +1,15 @@
+## DB migration scripts for OpenHub
+
+* SQL schema should be handled by Flyway, which does apply all the scripts in the migration folder
+with respect to the selected db engine.
+* All scripts should be immutable, once added & applied, then they should not be changes. There is naming convention in place,
+scripts should start with VX_X__ version, as it is default for Flyway.
+* Interesting configuration properties:
+    ```
+    flyway.baseline-on-migrate = (true/false)
+    
+    - whether to automatically call baseline when migrate is executed against a non-empty schema with no metadata table. This schema will then 
+    be baselined with the baselineVersion before executing the migrations. Only migrations above baselineVersion will then be applied.
+    ```
+
+* See flyway documentation (https://flywaydb.org/documentation/) for more information.