Update Dockerfile

Dockerfile

@@ -37,6 +37,10 @@ RUN git clone https://github.com/guardianproject/NetCipher.git /netcipher && \
     sed -i 's|distributionSha256Sum=.*|distributionSha256Sum=7ba68c54029790ab444b39d7e293d3236b2632631fb5f2e012bb28b4ff669e4b|' gradle/wrapper/gradle-wrapper.properties && \
     # local.propertiesを作成
     echo "sdk.dir=/sdk" > /netcipher/local.properties && \
+    # Mavenプラグインの追加
+    echo "plugins { id 'maven' }" >> /netcipher/build.gradle && \
+    # Mavenリポジトリの追加
+    echo "repositories { mavenCentral() }" >> /netcipher/build.gradle && \
     ./gradlew build && \
     mkdir -p /app/app/libs && \
     cp /netcipher/netcipher/build/libs/netcipher.jar /app/app/libs/