Update Dockerfile

Dockerfile

@@ -1,16 +1,18 @@
-FROM ubuntu:12.04
+FROM ubuntu:18.10
 MAINTAINER Amit Bakshi <ambakshi@gmail.com>
 
 ENV DEBIAN_FRONTEND=noninteractive
-RUN apt-get update -yq
-RUN apt-get install -yq python-software-properties
-RUN add-apt-repository -y ppa:ubuntu-toolchain-r/test
-RUN apt-get update -yq
-RUN apt-get install -yq build-essential gcc-4.8 g++-4.8 cmake make bison flex libpthread-stubs0-dev
-RUN update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-4.6 60 --slave /usr/bin/g++ g++ /usr/bin/g++-4.6
-RUN update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-4.8 40 --slave /usr/bin/g++ g++ /usr/bin/g++-4.8
-RUN echo 2 | update-alternatives --config gcc
+RUN apt-get update -yq && apt-get install -yq \
+    build-essential \
+    gcc \
+    g++ \
+    cmake \
+    make \
+    libpthread-stubs0-dev
 ADD . /app
 WORKDIR /app/build
 RUN cmake -G 'Unix Makefiles' ..
-CMD ["/usr/bin/make","-j2"]
+RUN /usr/bin/make -j8
+RUN ./pbrt_test
+
+