Selenium Remote Standalone Server - Driver unknown

I have a docker container in Google Cloud Platform Run with Firefox, Gecko and the Selenium Standalone Server Jar file version 4.0.0-alpha-1. With this i have this image:

FROM ubuntu:bionic
LABEL maintainer="Matheus Carvalho Gomes Moreira, matheus@hrestart.com.br"
EXPOSE 4444
ENV PORT 4444
ENV VERSION "V6.1"

# Systems update
RUN apt-get update && apt-get install -y \
    python3 python3-pip \
    fonts-liberation libappindicator3-1 libasound2 libatk-bridge2.0-0 \
    libnspr4 libnss3 lsb-release xdg-utils libxss1 libdbus-glib-1-2 \
    curl unzip wget \
    xvfb

# install java and selenium-server-standalone

RUN apt-get install openjdk-8-jdk -y
RUN wget -O /home/selenium-standalone.jar http://selenium-release.storage.googleapis.com/4.0/selenium-server-standalone-4.0.0-alpha-1.jar

# setup Java Environment

RUN export JAVA_HOME=/usr/lib/jvm/java-8-openjdk-amd64
RUN export PATH=$PATH:$JAVA_HOME/bin

# install geckodriver and firefox

RUN GECKODRIVER_VERSION=`curl https://github.com/mozilla/geckodriver/releases/latest | grep -Po 'v[0-9]+.[0-9]+.[0-9]+'` && \
    wget https://github.com/mozilla/geckodriver/releases/download/$GECKODRIVER_VERSION/geckodriver-$GECKODRIVER_VERSION-linux64.tar.gz && \
    tar -zxf geckodriver-$GECKODRIVER_VERSION-linux64.tar.gz -C /usr/local/bin && \
    chmod +x /usr/local/bin/geckodriver && \
    rm geckodriver-$GECKODRIVER_VERSION-linux64.tar.gz

RUN FIREFOX_SETUP=firefox-setup.tar.bz2 && \
    apt-get purge firefox && \
    wget -O $FIREFOX_SETUP "https://download.mozilla.org/?product=firefox-latest&os=linux64" && \
    tar xjf $FIREFOX_SETUP -C /opt/ && \
    ln -s /opt/firefox/firefox /usr/bin/firefox && \
    rm $FIREFOX_SETUP

CMD tail -f /dev/null
CMD DISPLAY=:1 xvfb-run java -jar /home/selenium-standalone.jar

And my client:

FirefoxOptions options = new FirefoxOptions();
driver = new RemoteWebDriver(new URL("${URL_TO_CONTAINER}"), options);

But when i try to create a instance of the remote driver accesing the endpoint, it gives this error:

Unable to create new service: GeckoDriverService
Build info: version: '4.0.0-alpha-1', revision: 'd1d3728cae', time: '2019-04-24T16:15:24'
System info: host: 'localhost', ip: '127.0.0.1', os.name: 'Linux', os.arch: 'amd64', os.version: '4.4.0', java.version: '1.8.0_242'
Driver info: driver.version: unknown

I searched it out and probably it´s because it can´t find Firefox and Gecko installed to initialize the service. Anyone has any thoughts?

I haven't worked with geckodrivers, but I found this project, which you can use as test and then figure out on the code how to set up the drivers and the next article to how to set up the application with selenium in a docker container.