Add instructions for building with docker

README.md

@@ -55,6 +55,22 @@ conditionally subscribe the `System` object to the new START, START_CFM, STOP, a
 
 lastly, route any desired read and write host commands to the new module in the switch statement in the `DELEGATE_PROCESS_COMMAND` event in `source/Delegate.cpp`
 
+### Building with docker
+
+First build the `adafruit-seesaw-builder` container:
+
+```
+docker build --platform linux/amd64 -f scripts/adafruit-seesaw-builder.Dockerfile --tag adafruit-seesaw-builder .
+```
+
+Then use it to build, e.g.:
+
+```
+docker run --platform linux/amd64 -v "$(pwd):/seesaw" -w /seesaw adafruit-seesaw-builder make BOARD=samd09Breakout
+```
+
+Since the above make command mounts the current directory as a docker volume, build files will show up in `build/` as usual.  
+
 # Future Work
 
 Much of the boilerplate work listed above could be automated away using the preprocessor and other build tools so only the new module files would need to be edited.

scripts/adafruit-seesaw-builder.Dockerfile

@@ -0,0 +1,21 @@
+FROM ubuntu:xenial
+
+RUN apt-get update && apt-get install -y \
+    curl \
+    libexpat1 \
+    libisl15 \
+    libmpc3 \
+    libmpfr4 \
+    python \
+    libpython2.7 \
+    make
+
+RUN mkdir /debs
+
+WORKDIR /debs
+
+RUN curl -LO https://s3.amazonaws.com/adafruit-circuit-python/gcc-arm-embedded_7-2018q2-1~xenial1_amd64.deb
+
+RUN echo "8c359c83adf69a8e3be27f239e14725bb000fdbc0b2f3dc14e9b7654dbcf89ce gcc-arm-embedded_7-2018q2-1~xenial1_amd64.deb" | sha256sum --check
+
+RUN dpkg -i gcc-arm-embedded_7-2018q2-1~xenial1_amd64.deb