Add "How-to: Implement core services with JPA"

docs/modules/guides/examples/docs-modules-guides-examples.gradle

@@ -0,0 +1,32 @@
+plugins {
+    //id 'org.springframework.boot' version '2.6.2'
+    //id 'io.spring.dependency-management' version '1.0.11.RELEASE'
+    id 'java'
+}
+
+group = 'org.springframework.security'
+version = '0.0.1-SNAPSHOT'
+sourceCompatibility = '11'
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    implementation platform('org.springframework.boot:spring-boot-dependencies:2.6.2')
+    implementation 'org.springframework.boot:spring-boot-starter-data-jpa'
+    implementation 'org.springframework.boot:spring-boot-starter-oauth2-client'
+    implementation 'org.springframework.boot:spring-boot-starter-oauth2-resource-server'
+    implementation 'org.springframework.boot:spring-boot-starter-security'
+    implementation 'org.springframework.boot:spring-boot-starter-thymeleaf'
+    implementation 'org.springframework.boot:spring-boot-starter-web'
+    implementation 'org.springframework.security:spring-security-oauth2-authorization-server:0.2.1'
+    implementation 'org.thymeleaf.extras:thymeleaf-extras-springsecurity5'
+    runtimeOnly 'com.h2database:h2'
+    testImplementation 'org.springframework.boot:spring-boot-starter-test'
+    testImplementation 'org.springframework.security:spring-security-test'
+}
+
+test {
+    useJUnitPlatform()
+}