Add env vars to allow other postgres targets

Also, support SSL for AWS RDS postgres. If needed in the future,
we could add more flexibility to what certificate to use, but
I didn't want to make the .env too complicated for now.

compose/django/entrypoint.sh

@@ -12,16 +12,31 @@ export REDIS_URL=redis://redis:6379
 if [ -z "$POSTGRES_USER" ]; then
     export POSTGRES_USER=postgres
 fi
+if [ -z "$POSTGRES_HOST" ]; then
+    export POSTGRES_HOST=postgres
+fi
+if [ -z "$POSTGRES_DB" ]; then
+    export POSTGRES_DB=postgres
+fi
+
+apt-get install -y ca-certificates wget
+wget https://s3.amazonaws.com/rds-downloads/rds-ca-2015-root.pem -P /usr/local/share/ca-certificates/
+update-ca-certificates
+
 
-export DATABASE_URL=postgres://$POSTGRES_USER:$POSTGRES_PASSWORD@postgres:5432/$POSTGRES_USER
+export DATABASE_URL=postgres://$POSTGRES_USER:$POSTGRES_PASSWORD@$POSTGRES_HOST:5432/$POSTGRES_DB
 
 
 function postgres_ready(){
 python << END
 import sys
 import psycopg2
+if "$POSTGRES_USE_AWS_SSL".lower() == 'true':
+    kwargs = {"sslrootcert": "rds-ca-2015-root.pem", "sslmode": "require"}
+else:
+    kwargs = {}
 try:
-    conn = psycopg2.connect(dbname="$POSTGRES_USER", user="$POSTGRES_USER", password="$POSTGRES_PASSWORD", host="postgres")
+    conn = psycopg2.connect(dbname="$POSTGRES_DB", user="$POSTGRES_USER", password="$POSTGRES_PASSWORD", host="$POSTGRES_HOST", **kwargs)
 except psycopg2.OperationalError:
     sys.exit(-1)
 sys.exit(0)

config/settings/common.py

@@ -111,6 +111,9 @@
 }
 DATABASES['default']['ATOMIC_REQUESTS'] = True
 
+if env.bool('POSTGRES_USE_AWS_SSL', False):
+    DATABASES['default']['OPTIONS'] = {'sslrootcert': 'rds-ca-2015-root.pem', 'sslmode': 'require'}
+
 
 # GENERAL CONFIGURATION
 # ------------------------------------------------------------------------------

env.example

@@ -1,7 +1,10 @@
 
 # PostgreSQL
+POSTGRES_HOST=postgres
+POSTGRES_DB=postgresuser
 POSTGRES_PASSWORD=mysecretpass
 POSTGRES_USER=postgresuser
+POSTGRES_USE_AWS_SSL=false
 
 # General settings
 DJANGO_ADMIN_URL=