[docker] add rustup install for CI build

docker/ci/Dockerfile

@@ -3,6 +3,10 @@ LABEL maintainer="felix.ruess@gmail.com"
 
 RUN sh -c 'echo "deb http://packages.osrfoundation.org/gazebo/ubuntu-stable `lsb_release -cs` main" > /etc/apt/sources.list.d/gazebo-stable.list'
 RUN wget http://packages.osrfoundation.org/gazebo.key -O - | apt-key add -
+RUN curl https://sh.rustup.rs -sSf | sh -s -- -y --default-toolchain nightly
+RUN /bin/bash -c "source $HOME/.cargo/env; \
+    rustup target add thumbv7em-none-eabihf; \
+    rustup target add x86_64-unknown-linux-gnu"
 
 RUN DEBIAN_FRONTEND=noninteractive apt-get update && apt-get install -y \
     g++-arm-linux-gnueabi \