Thanks for the help guys =)
This dockerfile actually helped me fix everything:
# install cron and R package dependencies
RUN apt-get update && apt-get install -y \
cron \
nano \
tdsodbc \
odbc-postgresql \
libsqliteodbc \
## clean up
&& apt-get clean \
&& rm -rf /var/lib/apt/lists/ \
&& rm -rf /tmp/downloaded_packages/ /tmp/*.rds
RUN apt-get update \
&& apt-get install --yes --no-install-recommends \
apt-transport-https \
curl \
gnupg \
unixodbc-dev \
&& curl https://packages.microsoft.com/keys/microsoft.asc | apt-key add - \
&& curl https://packages.microsoft.com/config/debian/9/prod.list > /etc/apt/sources.list.d/mssql-release.list \
&& apt-get update \
&& ACCEPT_EULA=Y apt-get install --yes --no-install-recommends msodbcsql17 \
&& install2.r odbc \
&& apt-get clean \
&& rm -rf /var/lib/apt/lists/* \
&& rm -rf /tmp/*```