diff --git a/.gitignore b/.gitignore
index 695622cf28a2079693d0ac62e973593386c93cf0..9609af04ffafc39ffec22dc640ba9df07562491d 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,4 @@
+.DS_Store
 .env
 data/
 docker-compose.override.yml
diff --git a/README.md b/README.md
index 1a324616701c4e80b03f28c2668e64ff26a4b467..dc10926cc23e8faaf0120c10a93a902da7212000 100644
--- a/README.md
+++ b/README.md
@@ -8,6 +8,7 @@ The easiest is to use our `docker-compose.yml`.
 Make sure you have [docker-compose](http://docs.docker.com/compose/install/) installed. And then:
 
 ```
+docker network create lb_web
 git clone https://github.com/indiehosters/discourse.git
 cd discourse
 ./scripts/install
@@ -40,3 +41,22 @@ web:
     - "80:80"
 ...
 ```
+
+##Environment variables
+
+./scripts/install expects certain environment variables to be in place.
+You will be asked for these values if they do not already exist.
+
+```
+VIRTUAL_HOST=host-domain
+DISCOURSE_SMTP_ADDRESS=smtp-host
+DISCOURSE_SMTP_USER_NAME=smtp-host-username
+DISCOURSE_SMTP_PASSWORD=smtp-host-password
+DISCOURSE_DB_PASSWORD=postgres-database-password
+POSTGRES_PASSWORD=postgres-database-password
+SUBNET=0
+POSTGRES_VERSION=10.6
+```
+
+You can prepopulate these environment variables by copying example.env to .env and changing the values to suit your environment.
+
diff --git a/example.env b/example.env
new file mode 100644
index 0000000000000000000000000000000000000000..1c758692bee10604d2ef0ee13c9a4929f31d7b04
--- /dev/null
+++ b/example.env
@@ -0,0 +1,8 @@
+VIRTUAL_HOST=host-domain
+DISCOURSE_SMTP_ADDRESS=smtp-host
+DISCOURSE_SMTP_USER_NAME=smtp-host-username
+DISCOURSE_SMTP_PASSWORD=smtp-host-password
+DISCOURSE_DB_PASSWORD=postgres-database-password
+POSTGRES_PASSWORD=postgres-database-password
+SUBNET=0
+POSTGRES_VERSION=10.6
diff --git a/scripts/install b/scripts/install
index 9fc21eb670ee7cc30f9fd70b83913d0839724849..0df6078abc5319a7623963d7d3d6a6a8e552ff98 100755
--- a/scripts/install
+++ b/scripts/install
@@ -1,20 +1,50 @@
 #!/bin/bash -eux
 
-PG_PASSWORD=`< /dev/urandom tr -dc _A-Z-a-z-0-9 | head -c${1:-32};echo;`
 
-echo "DISCOURSE_SMTP_ADDRESS=${MAIL_HOST}" > .env
-echo "DISCOURSE_SMTP_USER_NAME=${MAIL_USER}" >> .env
-echo "DISCOURSE_SMTP_PASSWORD=${MAIL_PASS}" >> .env
-echo "DISCOURSE_DB_PASSWORD=${PG_PASSWORD}" >> .env
-echo "POSTGRES_PASSWORD=${PG_PASSWORD}" >> .env
+# https://stackoverflow.com/questions/19331497/set-environment-variables-from-file-of-key-pair-values#20909045
+# clear enviromnet variables listed in .env
+unset $(grep -v '^#' .env | sed -E 's/(.*)=.*/\1/' | xargs)
+# load .env.
+export $(grep -v '^#' .env | xargs -d '\n')
+export $(grep -v '^#' .env | xargs -0)
+# https://stackoverflow.com/questions/19331497/set-environment-variables-from-file-of-key-pair-values#20909045
+
+
+if [ -z ${VIRTUAL_HOST+x} ]; then 
+	echo -n "Enter VIRTUAL_HOST: "; read VIRTUAL_HOST ; else 
+	echo "VIRTUAL_HOST is set to '$VIRTUAL_HOST'"; fi
+	
+if [ -z ${DISCOURSE_SMTP_ADDRESS+x} ]; then 
+	echo -n "Enter DISCOURSE_SMTP_ADDRESS: "; read DISCOURSE_SMTP_ADDRESS ; else 
+	echo "DISCOURSE_SMTP_ADDRESS is set to '$DISCOURSE_SMTP_ADDRESS'"; fi
+		
+if [ -z ${DISCOURSE_SMTP_USER_NAME+x} ]; then 
+	echo -n "Enter DISCOURSE_SMTP_USER_NAME: "; read DISCOURSE_SMTP_USER_NAME ; else 
+	echo "DISCOURSE_SMTP_USER_NAME is set to '$DISCOURSE_SMTP_USER_NAME'"; fi
+		
+if [ -z ${DISCOURSE_SMTP_PASSWORD+x} ]; then 
+	echo -n "Enter DISCOURSE_SMTP_PASSWORD: "; read DISCOURSE_SMTP_PASSWORD ; else 
+	echo "DISCOURSE_SMTP_PASSWORD is set to '$DISCOURSE_SMTP_PASSWORD'"; fi
+		
+if [ -z ${DISCOURSE_DB_PASSWORD+x} ]; then 
+	# https://unix.stackexchange.com/a/217276/111699 handle tr: Illegal byte sequence on Mac OSX. 
+	DISCOURSE_DB_PASSWORD=$(perl -pe 'binmode(STDIN, ":bytes"); tr/A-Za-z0-9_\!\@\#\$\%\^\&\*\(\)-+=//dc;' < /dev/urandom | head -c 32 ; echo); else
+	echo "DISCOURSE_DB_PASSWORD is set to '$DISCOURSE_DB_PASSWORD'"; fi
+
+echo "VIRTUAL_HOST=${VIRTUAL_HOST}"	> .env
+echo "DISCOURSE_SMTP_ADDRESS=${DISCOURSE_SMTP_ADDRESS}" >> .env
+echo "DISCOURSE_SMTP_USER_NAME=${DISCOURSE_SMTP_USER_NAME}" >> .env
+echo "DISCOURSE_SMTP_PASSWORD=${DISCOURSE_SMTP_PASSWORD}" >> .env
+echo "DISCOURSE_DB_PASSWORD=${DISCOURSE_DB_PASSWORD}" >> .env
+echo "POSTGRES_PASSWORD=${DISCOURSE_DB_PASSWORD}" >> .env
 echo "SUBNET=${SUBNET:-0}" >> .env
 echo "POSTGRES_VERSION=10.6" >> .env
 
 mkdir -p ./data/{assets,uploads,backups,redis,postgres}
 
-chown -R 1000:1000 ./data/
+chown -R 1000:1000 ./data || true # || true handles if chown -R 1000:1000 fails on Mac OSX
 
-VIRTUAL_HOST=${URL} docker-compose run app bash -c "sleep 60 && bundle exec rake maxminddb:get db:migrate assets:precompile"
-VIRTUAL_HOST=${URL} docker-compose run app bash -c "rake admin:create"
+VIRTUAL_HOST=${VIRTUAL_HOST} docker-compose run app bash -c "sleep 60 && bundle exec rake maxminddb:get db:migrate assets:precompile"
+VIRTUAL_HOST=${VIRTUAL_HOST} docker-compose run app bash -c "bundle exec rake admin:create"
 
 echo "!!!Configure notification email in discourse settings!!!!!!"