issue #165 added dockerfile for ubuntu

docker/linux-ubuntu/Dockerfile

@@ -0,0 +1,35 @@
+FROM ubuntu:18.04
+
+RUN set -x \
+    && apt-get update \
+    && apt-get install -y libreadline-dev \
+    && apt-get install -y build-essential \
+    && apt-get install -y git wget \
+    && apt-get install -y zlib1g-dev \
+    && apt-get clean \
+    && mkdir -p /Software \
+    && wget -O "/Software/cmake-3.14.5-Linux-x86_64.tar.gz" "https://github.com/Kitware/CMake/releases/download/v3.14.5/cmake-3.14.5-Linux-x86_64.tar.gz" \
+    && cd /Software \
+    && tar xvf "cmake-3.14.5-Linux-x86_64.tar.gz" \
+    && rm -rf "/Software/cmake-3.14.5-Linux-x86_64.tar.gz" \
+    && wget -O "/Software/clang+llvm-8.0.0-x86_64-linux-gnu-ubuntu-18.04.tar.xz" "http://releases.llvm.org/8.0.0/clang+llvm-8.0.0-x86_64-linux-gnu-ubuntu-18.04.tar.xz" \
+    && cd /Software \
+    && tar xvf "clang+llvm-8.0.0-x86_64-linux-gnu-ubuntu-18.04.tar.xz" \
+    && rm -rf "/Software/clang+llvm-8.0.0-x86_64-linux-gnu-ubuntu-18.04.tar.xz" \
+    && mkdir -p /sources \
+    && cd /sources \
+    && git clone https://github.com/dibyendumajumdar/ravi.git \
+    && cd /sources/ravi \
+    && mkdir build \
+    && cd build \
+    && /Software/cmake-3.14.5-Linux-x86_64/bin/cmake -DSTATIC_BUILD=ON -DCMAKE_INSTALL_PREFIX=/Software/ravi -DLLVM_JIT=ON -DCMAKE_BUILD_TYPE=Release -DLLVM_DIR=/Software/clang+llvm-8.0.0-x86_64-linux-gnu-ubuntu-18.04/lib/cmake/llvm .. \
+    && make install \
+    && rm -rf /Software/cmake-3.14.5-Linux-x86_64 \
+    && rm -rf /Software/clang+llvm-8.0.0-x86_64-linux-gnu-ubuntu-18.04 \
+    && rm -rf /sources \
+    && apt-get autoremove \
+    && apt-get remove -y --purge git wget build-essential \
+    && apt-get clean
+
+ENV PATH /Software/ravi/bin:${PATH}
+