Docker images (#527)

with this change we're adding generation of 2 docker images - verifier and stub runner
we also added a project `spring-cloud-contract-stub-runner-boot` which contains a far jar with stub runner boot

fixes gh-526, gh-516

docker/spring-cloud-contract-docker/project/src/test/java/contracts/RestBase.java

@@ -0,0 +1,41 @@
+package contracts;
+
+import io.restassured.RestAssured;
+import org.junit.Before;
+import org.junit.ClassRule;
+import org.junit.runner.RunWith;
+import org.junit.validator.ValidateWith;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.test.context.junit4.SpringRunner;
+import org.springframework.util.StringUtils;
+
+/**
+ * @author Marcin Grzejszczak
+ */
+@RunWith(SpringRunner.class)
+@SpringBootTest(classes = RestBase.Config.class,
+		webEnvironment = SpringBootTest.WebEnvironment.NONE)
+public abstract class RestBase {
+
+	@Value("${APPLICATION_BASE_URL}") String url;
+	@Value("${APPLICATION_USERNAME:}") String username;
+	@Value("${APPLICATION_PASSWORD:}") String password;
+
+	@Before
+	public void setup() {
+		RestAssured.baseURI = this.url;
+		if (StringUtils.hasText(this.username)) {
+			RestAssured.authentication =
+					RestAssured.basic(this.username, this.password);
+		}
+	}
+
+	@Configuration
+	@EnableAutoConfiguration
+	protected static class Config {
+
+	}
+}