Add PiGallery2 (#932)

* Add PyGallery2

* add host path

* add review

* fix description

public/v4/apps/pigallery2.yml

@@ -0,0 +1,35 @@
+captainVersion: 4
+services:
+    $$cap_appname:
+        image: bpatrik/pigallery2:$$cap_version
+        environment:
+            NODE_ENV: production # set to 'debug' for full debug logging
+        volumes:
+            - $$cap_appname-config:/app/data/config
+            - $$cap_appname-db:/app/data/db
+            - $$cap_images:/app/data/images
+            - $$cap_appname-tmp:/app/data/tmp
+        restart: always
+caproverOneClickApp:
+    variables:
+        - id: $$cap_version
+          label: PiGallery2 Version
+          defaultValue: '1.9.5'
+          description: Check out their docker page for the valid tags https://hub.docker.com/r/bpatrik/pigallery2/tags
+          validRegex: /^([^\s^\/])+$/
+        - id: $$cap_images
+          label: Set path to images
+          description: Path containing your pictures library. IMPORTANT, this must be an existing directory on your host, otherwise the app crashes.
+          validRegex: /^/(?!/)/
+    instructions:
+        start: >-
+            This is a **fast** (like faster than your PC fast) **directory-first photo gallery website**, optimised for running on low resource servers (especially on raspberry pi).
+        end: >-
+            You're done! 😄
+
+            ⚠️ Default user: `admin` pass: `admin`. (It is not possible to change the admin password, you need to create another user and delete the default admin user).
+            Then restart the container.
+    displayName: 'PiGallery2'
+    isOfficial: true
+    description: A fast directory-first photo gallery website, with rich UI, optimized for running on low resource servers (especially on raspberry pi)
+    documentation: Taken from https://github.com/bpatrik/pigallery2/blob/master/docker/docker-compose/pigallery2-only/docker-compose.yml