Add powershell (#178)

powershell/Dockerfile

@@ -0,0 +1,21 @@
+FROM debian:sid
+MAINTAINER Christian Koep <christian.koep@fom-net.de>
+
+ENV POWERSHELL_VERSION 6.0.0-alpha.9
+
+RUN apt-get update && apt-get install -y \
+	ca-certificates \
+	curl \
+	libunwind8 \
+	libicu55 \
+	dpkg \
+	--no-install-recommends \
+	&& rm -rf /var/lib/apt/lists/*
+
+RUN cd /usr/src \
+	&& curl -L -O https://github.com/PowerShell/PowerShell/releases/download/v${POWERSHELL_VERSION}/powershell_${POWERSHELL_VERSION}-1ubuntu1.16.04.1_amd64.deb \
+	&& dpkg -i powershell_${POWERSHELL_VERSION}-1ubuntu1.16.04.1_amd64.deb \
+	&& apt-get install -fy \
+	&& rm -rf /var/lib/apt/lists/* /usr/src/*
+
+ENTRYPOINT [ "/usr/bin/powershell" ]