Install gecko driver to the compose-web light Docker image

ci/docker/compose-web/Dockerfile-Basic

@@ -15,6 +15,8 @@ RUN dpkg --add-architecture i386 && apt-get update -yqq && apt-get install -y \
     unzip \
     wget
 
+RUN wget https://github.com/mozilla/geckodriver/releases/download/v0.29.1/geckodriver-v0.29.1-linux64.tar.gz \
+    && tar -xvzf geckodriver-v0.29.1-linux64.tar.gz && mv geckodriver /usr/local/bin
 
 RUN export CHROME_DRIVER_VERSION=$(wget -qO- https://chromedriver.storage.googleapis.com/LATEST_RELEASE) \
     && wget https://chromedriver.storage.googleapis.com/${CHROME_DRIVER_VERSION}/chromedriver_linux64.zip -P ~/tmp