feat: use dockerfile-maven-plugin for building Docker image.

Usage:
- mvn package dockerfile:build for building WAR and an image
- mvn dockerfile:push for pushing an image to Docker registry

Fix #83

[ci skip]

Author: php-coder

docker/README.md

@@ -7,20 +7,17 @@ possible configurations, we support only those that are typically used:
   In this mode, it also runs in-memory database H2. This is roughly the same as
   executing `mvn spring-boot:run` command but inside a Docker container.
 
-  * Create a WAR file that will be used for building an image:
+  * Create a WAR file and build the image `phpcoder/mystamps:latest`:
     ```console
-    $ mvn package
-    $ cd docker
-    $ ln -fv ../target/mystamps.war mystamps.war
+    $ mvn package dockerfile:build
     ```
-    By the way, don't forget to remove this hard link after using.
-  * Build an image and run a container with `docker-compose`:
+  * Run a container with `docker-compose`:
     ```console
+    $ cd docker
     $ docker-compose up -d
     ```
-  * The same but with a plain Docker:
+    or with a plain Docker:
     ```console
-    $ docker build -t mystamps:latest .
-    $ docker run -d -p 8080:8080 --cap-drop all mystamps:latest
+    $ docker run -d -p 8080:8080 --cap-drop all phpcoder/mystamps:latest
     ```
 

docker/docker-compose.yml

@@ -2,8 +2,7 @@ version: '3'
 
 services:
   web:
-    build: ./
-    image: mystamps:latest
+    image: phpcoder/mystamps:latest
     cap_drop:
       - "ALL"
     ports:

pom.xml

@@ -491,6 +491,7 @@
 		<!-- Disable XML reports by default. Enabled manually by passing -DdisableXmlReport=false in CI environment -->
 		<disableXmlReport>true</disableXmlReport>
 
+		<dockerfile.plugin.version>1.4.6</dockerfile.plugin.version>
 		<enforcer.plugin.version>1.4.1</enforcer.plugin.version>
 		<failsafe.plugin.version>2.22.0</failsafe.plugin.version>
 		<fest.assert.version>2.0M8</fest.assert.version>
@@ -719,6 +720,17 @@
 				</executions>
 			</plugin>
 
+			<plugin>
+				<groupId>com.spotify</groupId>
+				<artifactId>dockerfile-maven-plugin</artifactId>
+				<version>${dockerfile.plugin.version}</version>
+				<configuration>
+					<repository>phpcoder/mystamps</repository>
+					<!-- TODO: set it to docker/ after https://github.com/spotify/dockerfile-maven/pull/89 will be merged -->
+					<contextDirectory>target</contextDirectory>
+				</configuration>
+			</plugin>
+			
 			<plugin>
 				<groupId>org.apache.maven.plugins</groupId>
 				<artifactId>maven-checkstyle-plugin</artifactId>
@@ -846,6 +858,28 @@
 				<groupId>org.apache.maven.plugins</groupId>
 				<artifactId>maven-resources-plugin</artifactId>
 				<version>${resources.plugin.version}</version>
+				<executions>
+					<!-- TODO: remove this workaround after merging https://github.com/spotify/dockerfile-maven/pull/89 -->
+					<execution>
+						<id>copy-docker-resources</id>
+						<goals>
+							<goal>copy-resources</goal>
+						</goals>
+						<phase>prepare-package</phase>
+						<configuration>
+							<!-- copy docker/Dockerfile to target/ -->
+							<outputDirectory>target</outputDirectory>
+							<resources>
+								<resource>
+									<directory>${basedir}/docker</directory>
+									<includes>
+										<include>Dockerfile</include>
+									</includes>
+								</resource>
+							</resources>
+						</configuration>
+					</execution>
+				</executions>
 			</plugin>
 
 			<plugin>