Update docs

- Add more repository config docs.
- Relates to #270

spring-statemachine-data/jpa/src/test/java/org/springframework/statemachine/data/jpa/docs/DocsJpaRepositorySampleTests1.java

@@ -32,19 +32,19 @@ public class DocsJpaRepositorySampleTests1 {
 		TransitionRepository<JpaRepositoryTransition> transitionRepository;
 
 		void addConfig() {
-			JpaRepositoryState state1 = new JpaRepositoryState("machine1", "S1", true);
-			JpaRepositoryState state2 = new JpaRepositoryState("machine2", "S2", false);
-			JpaRepositoryState state3 = new JpaRepositoryState("machine1", "S3", true);
-			JpaRepositoryState state4 = new JpaRepositoryState("machine2", "S4", false);
-			stateRepository.save(state1);
-			stateRepository.save(state2);
-			stateRepository.save(state3);
-			stateRepository.save(state4);
+			JpaRepositoryState stateS1 = new JpaRepositoryState("S1", true);
+			JpaRepositoryState stateS2 = new JpaRepositoryState("S2");
+			JpaRepositoryState stateS3 = new JpaRepositoryState("S3");
 
-			JpaRepositoryTransition transition1 = new JpaRepositoryTransition("machine1", state1, state2, "E1");
-			JpaRepositoryTransition transition2 = new JpaRepositoryTransition("machine2", state3, state4, "E2");
-			transitionRepository.save(transition1);
-			transitionRepository.save(transition2);
+			stateRepository.save(stateS1);
+			stateRepository.save(stateS2);
+			stateRepository.save(stateS3);
+
+			JpaRepositoryTransition transitionS1ToS2 = new JpaRepositoryTransition(stateS1, stateS2, "E1");
+			JpaRepositoryTransition transitionS2ToS3 = new JpaRepositoryTransition(stateS2, stateS3, "E2");
+
+			transitionRepository.save(transitionS1ToS2);
+			transitionRepository.save(transitionS2ToS3);
 		}
 // end::snippetA[]
 	}