Automate HassIO builds using Gitlab CI (#52)

* Add Gitlab CI

* Fix aarch64 edge build

docker/Dockerfile.armhf

@@ -0,0 +1,20 @@
+# Dockerfile for armhf version of HassIO add-on
+FROM homeassistant/armhf-base:latest
+
+RUN apk add --no-cache \
+        python2 \
+        py2-pip \
+        git \
+        openssh \
+        libc6-compat \
+    && \
+    pip install --no-cache-dir --no-binary :all: platformio && \
+    platformio settings set enable_telemetry No
+
+COPY docker/platformio-esp8266.ini /pio/platformio.ini
+RUN platformio run -d /pio; rm -rf /pio
+
+COPY . .
+RUN pip install --no-cache-dir --no-binary :all: -e .
+
+CMD ["esphomeyaml", "/config/esphomeyaml", "dashboard"]