Add a Dockerfile that validates that the crate can be compiled with nightly Rust

Author: dylanmckay

.dockerignore

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+target/
+Dockerfile

Dockerfile.ci

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+FROM ubuntu:18.04
+
+RUN useradd -m avr-rust
+
+# Install dependencies
+RUN apt-get update -y && apt-get install -y wget gcc binutils gcc-avr avr-libc
+
+RUN mkdir -p /code && chown avr-rust:avr-rust /code
+
+USER avr-rust
+
+# Install Rustup along with nightly
+RUN wget -q https://sh.rustup.rs -O /tmp/rustup.sh && sh /tmp/rustup.sh -y --profile minimal --default-toolchain nightly -c rust-src --quiet
+ENV PATH=/home/avr-rust/.cargo/bin:$PATH
+
+COPY --chown=avr-rust:avr-rust . /code/blink
+
+WORKDIR /code/blink
+
+CMD ["cargo", "build", "-Z", "build-std=core", "--target", "avr-atmega328p.json", "--release"]