Add file to build docker image.

Author: CodeNinjaEvan

Dockerfile

@@ -0,0 +1,11 @@
+FROM tronprotocol/tron-gradle
+
+RUN set -o errexit -o nounset \
+    && echo "git clone" \
+    && git clone https://github.com/tronprotocol/java-tron.git \
+    && cd java-tron \
+    && gradle build
+
+WORKDIR /java-tron
+
+EXPOSE 18888