minor adjustments (#41)

Author: ciur

docs/settings/overview.md

@@ -7,5 +7,5 @@ Environment variables have following format:
 
     PAPERMERGE__<section>__<name>
 
-double underscores are used as delimiter; environment variables names must all
+double underscores are used as delimiter; environment variables names must be all
 upper case.

docs/setup/docker.md

@@ -7,13 +7,13 @@
 
 ## TL;DR
 
-The only two required environment variables are `PAPERMERGE__MAIN__SECRET_KEY` and `PAPERMERGE__AUTH__PASSWORD`:
+The only two required environment variables are `PAPERMERGE__SECURITY__SECRET_KEY` and `PAPERMERGE__AUTH__PASSWORD`:
 
 ```console
 docker run -p 9400:8000 \
-    -e PAPERMERGE__MAIN__SECRET_KEY=abc \
+    -e PAPERMERGE__SECURITY__SECRET_KEY=abc \
     -e PAPERMERGE__AUTH__PASSWORD=123 \
-    papermerge/papermerge:3.0
+    papermerge/papermerge:{{ extra.docker_image_version }}
 ```
 
 Point your web browser to http://localhost:9400 and you will see login screen:
@@ -38,13 +38,13 @@ Official {{ extra.project  }} docker images are stored in <a href="https://hub.d
 The recommended way to get the {{ extra.project }} Docker Image is to pull the prebuilt image from the <a href=" https://github.com/papermerge/papermerge-core/pkgs/container/papermerge" class="external-link" target="_blank">github repository packages</a>:
 
 ```console
-docker pull papermerge/papermerge:3.0
+docker pull papermerge/papermerge:{{ extra.docker_image_version }}
 ```
 
 To use a specific version, you can pull a versioned tag. You can view the list of available versions in the github repository packages:
 
 ```console
-docker pull papermerge/papermerge:3.0
+docker pull papermerge/papermerge:{{ extra.docker_image_version }}
 ```
 
 
@@ -57,7 +57,7 @@ By default {{ extra.project }} uses sqlite3 database. In order to use PostgreSQL
 
     services:
       app:
-        image: papermerge/papermerge:3.0
+        image: papermerge/papermerge:{{ extra.docker_image_version }}
         environment:
           - PAPERMERGE__SECURITY__SECRET_KEY=abc
           - PAPERMERGE__AUTH__PASSWORD=12345

mkdocs.yml

@@ -74,6 +74,7 @@ theme:
 repo_url: https://github.com/ciur/papermerge
 extra:
   project: Papermerge  # custom variable for macros plugin
+  docker_image_version: 3.0a2  # latest docker image version e.g. 3.0, 3.0.1, 3.1.9, 3.0a1
   version:
     provider: mike
   social: