Add PDS credentials env file for service auth

.gitignore

@@ -4,3 +4,4 @@ go.*
 feeds/
 feeds.db/
 1440.db
+pds.env

docker-compose.yml

@@ -3,6 +3,8 @@ services:
     build: .
     container_name: app-1440-news
     restart: unless-stopped
+    env_file:
+      - pds.env
     volumes:
       - ./feeds:/app/feeds
       - ./vertices.txt.gz:/app/vertices.txt.gz:ro

pds.env.example

@@ -0,0 +1,4 @@
+# PDS credentials for posting
+# Copy to pds.env and fill in values
+PDS_HOST=https://1440.news
+PDS_ADMIN_PASSWORD=your_admin_password