Update Dockerfile

Dockerfile

@@ -46,10 +46,17 @@ RUN git clone https://github.com/pyenv/pyenv.git /builder/.pyenv && \
     PYTHON_CONFIGURE_OPTS="--enable-shared" pyenv install --force 3.5.5 && \
     PYTHON_CONFIGURE_OPTS="--enable-shared" pyenv install --force 3.6.4
 
+USER root
+ADD xvfb.sh /etc/init.d/xvfb
+RUN chmod a+x /etc/init.d/xvfb
+ADD xvfb-run.sh /usr/bin/xvfb-run
+RUN chmod a+x /usr/bin/xvfb-run
+
+
 USER root
 RUN export XVFBARGS="-screen 0 1280x1024x24" && \
     export DISPLAY=:99.0  && \
-    sh -e /etc/init.d/xvfb start  && \
+    /usr/bin/xvfb-run && \
     sleep 3  && \
     curl -L https://download.qt.io/official_releases/qt/5.9/5.9.4/qt-opensource-linux-x64-5.9.4.run --output qt-opensource-linux-x64-5.9.4.run && \
     chmod +x qt-opensource-linux-x64-5.9.4.run && \