Add Dockerfile to build an image with Alpine linux + monit

Dockerfile

@@ -0,0 +1,25 @@
+FROM alpine:3.7
+
+LABEL maintainer="Luis Miguel Vicente Fuentes <kijart@gmail.com>"
+
+# monit environment variables
+ENV MONIT_VERSION=5.25.1 \
+    MONIT_HOME=/opt/monit \
+    MONIT_URL=https://mmonit.com/monit/dist \
+    PATH=$PATH:/opt/monit/bin
+
+# Compile and install monit
+RUN \
+    echo "*** compile and install monit ***" && \
+    apk add --update gcc musl-dev make libressl-dev file zlib-dev && \
+    mkdir -p /opt/src; cd /opt/src && \
+    wget -qO- ${MONIT_URL}/monit-${MONIT_VERSION}.tar.gz | tar xz && \
+    cd /opt/src/monit-${MONIT_VERSION} && \
+    ./configure --prefix=${MONIT_HOME} --without-pam && \
+    make && make install && \
+    apk del gcc musl-dev make libressl-dev file zlib-dev && \
+    rm -rf /var/cache/apk/* /opt/src
+
+EXPOSE 2812
+
+CMD ["monit", "-I", "-B"]