!4 添加 Dockerfile，方便使用

Merge pull request !4 from blankman/master

Dockerfile

@@ -0,0 +1,7 @@
+FROM java:8-jre-alpine
+
+ENV PORT 8081
+
+ADD target/JrebelBrainsLicenseServerforJava-1.0-SNAPSHOT-jar-with-dependencies.jar /JrebelBrains.jar
+CMD java -jar /JrebelBrains.jar -p $PORT
+