Improve Docker build; reduce image size & layer count

Reducing layer count improves Docker performance, and is best-practice.
Avoid packing & sending .git tree into Docker build system.
Clean up apt archives to reduce image size.

.dockerignore

@@ -0,0 +1 @@
+.git

Dockerfile

@@ -3,11 +3,9 @@
 FROM ubuntu:trusty
 MAINTAINER Kyle Johnson <kjohnson@gnulnx.net>
 
-# Let the container know that there is no tty
-ENV DEBIAN_FRONTEND noninteractive
-
 # Resynchronize the package index files 
-RUN apt-get update && apt-get install -y \
+RUN apt-get update && \
+	DEBIAN_FRONTEND=noninteractive apt-get install -y \
 	libpolkit-gobject-1-dev build-essential libmysqlclient-dev libssl-dev libbz2-dev libpcre3-dev \
 	libdbi-perl libarchive-zip-perl libdate-manip-perl libdevice-serialport-perl libmime-perl libpcre3 \
 	libwww-perl libdbd-mysql-perl libsys-mmap-perl yasm cmake libjpeg-turbo8-dev \
@@ -16,7 +14,8 @@ RUN apt-get update && apt-get install -y \
 	mysql-server libvlc-dev libvlc5 libvlccore-dev libvlccore7 vlc-data libcurl4-openssl-dev \
 	libavformat-dev libswscale-dev libavutil-dev libavcodec-dev libavfilter-dev \
 	libavresample-dev libavdevice-dev libpostproc-dev libv4l-dev libtool libnetpbm10-dev \
-	libmime-lite-perl dh-autoreconf dpatch
+	libmime-lite-perl dh-autoreconf dpatch \
+	&& apt-get clean
 
 # Copy local code into our container
 ADD . /ZoneMinder
@@ -31,11 +30,8 @@ WORKDIR /ZoneMinder
 #RUN ./configure --with-libarch=lib/$DEB_HOST_GNU_TYPE --disable-debug --host=$DEB_HOST_GNU_TYPE --build=$DEB_BUILD_GNU_TYPE --with-mysql=/usr  --with-webdir=/var/www/zm --with-ffmpeg=/usr --with-cgidir=/usr/lib/cgi-bin --with-webuser=www-data --with-webgroup=www-data --enable-mmap=yes --enable-onvif ZM_SSL_LIB=openssl ZM_DB_USER=zm ZM_DB_PASS=zm
 RUN cmake .
 
-# Build ZoneMinder
-RUN make
-
-# Install ZoneMinder
-RUN make install
+# Build & install ZoneMinder
+RUN make && make install
 
 # ensure writable folders
 RUN ./zmlinkcontent.sh
@@ -43,10 +39,6 @@ RUN ./zmlinkcontent.sh
 # Adding the start script
 ADD utils/docker/start.sh /tmp/start.sh
 
-# Ensure we can run this
-# TODO - Files ADD'ed have 755 already...why do we need this?
-RUN chmod 755 /tmp/start.sh
-
 # give files in /usr/local/share/zoneminder/
 RUN chown -R www-data:www-data /usr/local/share/zoneminder/
 
@@ -65,7 +57,6 @@ RUN useradd -m -s /bin/bash -G sudo zoneminder
 RUN echo 'zoneminder:zoneminder' | chpasswd
 
 # Expose ssh and http ports
-EXPOSE 80
-EXPOSE 22
+EXPOSE 22 80
 
 CMD "/tmp/start.sh"