Immprove Dockerfile (use proper layer caching)

Dockerfile

@@ -1,26 +1,36 @@
 FROM ubuntu:utopic
 MAINTAINER jekkos
 RUN sed -i -e 's/archive.ubuntu.com\|security.ubuntu.com/old-releases.ubuntu.com/g' /etc/apt/sources.list
-RUN apt-get update
-RUN apt-get -y upgrade
-RUN DEBIAN_FRONTEND=noninteractive apt-get -y install mysql-client mysql-server apache2 libapache2-mod-php5 pwgen python-setuptools vim-tiny php5-mysql php5-gd php5-apcu nodejs npm curl
+RUN apt-get update && DEBIAN_FRONTEND=noninteractive apt-get install -y \
+    mysql-client \
+    mysql-server \
+    apache2 \
+    libapache2-mod-php5 \
+    pwgen python-setuptools \
+    vim-tiny \
+    php5-mysql \
+    php5-gd \
+    php5-apcu \
+    nodejs \
+    npm \
+    curl \
+    software-properties-common \
+    python \
+    git
 RUN easy_install supervisor
-ADD ./docker/foreground.sh /etc/apache2/foreground.sh
-ADD ./docker/supervisord.conf /etc/supervisord.conf
-RUN chmod 755 /etc/apache2/foreground.sh
-# Install dependencies 
-RUN apt-get install -y --no-install-recommends software-properties-common
-RUN apt-get install -y python git
 
-# Get latest Ospos source from Git
-ADD . /app
+COPY ./docker/foreground.sh /etc/apache2/foreground.sh
+COPY ./docker/supervisord.conf /etc/supervisord.conf
+RUN chmod 755 /etc/apache2/foreground.sh
+
+COPY . /app
 RUN ln -s /usr/bin/nodejs /usr/bin/node
 RUN cd app && npm install
 RUN npm install -g grunt-cli
 RUN ln -s /usr/local/bin/grunt /usr/bin/grunt
 
 RUN ln -fs /app/* /var/www/html
-ADD ./docker/start_container.sh /start_container.sh
+COPY ./docker/start_container.sh /start_container.sh
 RUN chmod 755 /start_container.sh
 EXPOSE 80 3306
 CMD ["/bin/bash", "/start_container.sh"]