Add instructions for building and running Docker images

GETTING_STARTED.md

@@ -11,7 +11,9 @@ password are required), run:
 On success, an "hpr_generator" directory will be created in the folder from 
 which the clone command was executed containing a local copy of the git repository.
 
-# Install required Perl modules
+# Building on local system
+
+## Install required Perl modules
 
 Installing the Perl modules is the most finicky part of the installation process. 
 The needed Perl modules can be found using the operating system's package 
@@ -34,7 +36,7 @@ apt install libconfig-std-perl \
 
 ```
 
-## Using CPAN to install the modules
+### Using CPAN to install the modules
 
 A cross platform method to install the needed modules is the Perl CPAN application. 
 Make sure that the [gcc](https://www.gnu.org/software/gcc/), 
@@ -55,7 +57,7 @@ cpan Tie::DBI
 cpan Text:CSV_XS
 ```
 
-## Testing for Perl module dependencies
+### Testing for Perl module dependencies
 
 A bash script is included in the utils directory that will list the Perl modules used by the site-generator and report whether the modules are installed on the current OS.
 
@@ -65,6 +67,37 @@ It can be run from any directory. To run from the utils directory:
 ./check-dependencies.sh
 ```
 
+# Building with Docker
+
+The docker file will copy the local version of the site-generator program, the templates directory, the LICENSE file,
+and the site.cfg file into the Docker image. For the docker image to run correctly it needs access to your local 
+hpr.db file and the output directory (defaults to "public_html"). The default site.cfg assumes the hpr.db is located 
+in the directory from which the site-generator is run. There are two ways to make the db available to the container:
+
+* Put the hpr.db file in the public_html folder and modify the driver option under the [DBI] section of the site.cfg to:<br>
+  ```driver: dbi:SQLite:public_html/hpr.db```
+* mount the hpr.db file into the container when starting up the container with the -v option: <br>
+  ```-v <path to db directory>/hpr.db:/usr/src/app/hpr.db```
+
+Build the image by running the following command from the hpr_generator directory:
+```docker run -t hpr/site-generator .```
+
+The first build will take a while. It must pull down the base container, perl-latest, and then pull down and build the 
+various Perl modules from CPAN. After the initial build, if you have modified your site.cfg file, templates dir, or the 
+site-generator program itself, builds will be very quick.
+
+## Running the container
+
+When runing the Docker image, your local output directory (typically public_html) must be mounted into the container using 
+the -v option. If you are using the default path for the hpr.db, then the local hpr.db file must also be mounted into the image.
+The following is an example of running the site-generator with default locations from the hpr_generator directory:
+```
+docker run \
+-v "$(pwd)/public_html":/usr/src/app/public_html \
+-v "$(pwd)/hpr.db":/usr/src/app/hpr.db \
+hpr/site-generator --help
+```
+
 # Create the HPR database
 
 The hpr_generator relies on information from a database to generate many of the 

README.md

@@ -2,6 +2,9 @@
 Static web page generator for the Hacker Public Radio website.
 
 ## Installation
+
+### On local system
+
 * Clone or download this repository
 * With SQLite
 	* Create the sqlite3 database from the hpr.sql MySQL dump file available on
@@ -31,6 +34,10 @@ Static web page generator for the Hacker Public Radio website.
     * Text::CSV_XS
     * HTML::Entities
 
+### Using Docker
+
+* run: `docker build -t hpr/site-generator .`
+
 * See the [Getting Started](GETTING_STARTED.md) tutorial for more details on
   installing the HPR generator.