message: Enable parallelization when execute make in Docker
diff: @@ -21,7 +21,7 @@ RUN apt-get update && apt-get install -y \
  RUN curl -L http://download.oracle.com/berkeley-db/db-4.8.30.tar.gz | tar -xz -C /tmp && \
  cd /tmp/db-4.8.30/build_unix && \
  ../dist/configure --enable-cxx --includedir=/usr/include/bdb4.8 --libdir=/usr/lib && \
  - make && make install && \
  + make -j$(nproc) && make install && \
  cd / && rm -rf /tmp/db-4.8.30
  # Create user to run daemon
  @@ -33,7 +33,7 @@ COPY . /tmp/zcoin/
  RUN cd /tmp/zcoin && \
  ./autogen.sh && \
  ./configure --without-gui --prefix=/usr && \
  - make && \
  + make -j$(nproc) && \
  make check && \
  make install && \
  cd / && rm -rf /tmp/zcoin
  