added initial spring boot setup with external postgres connection and openai api key

backend/src/main/java/com/vaessl/app/Application.java

@@ -0,0 +1,13 @@
+package com.vaessl.app;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class Application {
+
+	public static void main(String[] args) {
+		SpringApplication.run(Application.class, args);
+	}
+
+}

backend/src/main/resources/application.yaml

@@ -0,0 +1,27 @@
+spring:
+  application:
+    name: vaessl
+  config:
+    import: "optional:file:.env_dev[.properties]"
+  datasource:
+    url : ${DB_URL}
+    username: ${DB_USERNAME}
+    password: ${DB_PASSWORD}
+    driver-class-name: ${PG_DRIVER_CLASS_NAME}
+
+  jpa:
+    hibernate:
+      ddl-auto: update
+    show-sql: true
+
+  ai:
+    openai:
+      base-url: ${OPENAI_BASE_URL}
+      api-key: ${OPENAI_KEY}
+      chat:
+        options:
+          model: gpt-4o-mini
+
+  logging:
+    level:
+      org.springframework.boot.context.config: TRACE