[server] Allow specifying image tag from env

compose.yml

@@ -4,7 +4,7 @@ name: phylum
 services:
   server:
     container_name: phylum_server
-    image: shroff12/phylum
+    image: shroff12/phylum:${PHYLUM_IMAGE_TAG:-latest}
     volumes:
       - ${DATA_ROOT:-./data}/${STORAGE_LOCATION:-storage}:/app/storage
       - ${DATA_ROOT:-./data}/${CONFIG_LOCATION:-config.yml}:/app/config.yml

example.env

@@ -1,3 +1,6 @@
+## 
+# PHYLUM_IMAGE_TAG=latest
+
 ## Base path of container mounts
 # DATA_ROOT=./data
 
@@ -20,8 +23,8 @@ PHYLUM_DB_PASSWORD=phylum
 # For a full list of configuration parameters see the config.defaults.yml at
 # https://codeberg.org/shroff/phylum/.
 #
-# You can also use PHYLUM_* environment variables substituting '_' for '.',
-# i.e. PHYLUM_SERVER_PORT to override server.port, but it is recommended to
-# do that using the config.yml file.
+# You can also use PHYLUM_* environment variables substituting '_' for '.' to
+# override any config (i.e. PHYLUM_SERVER_PORT to override server.port), but
+# it is recommended to not do that unless you know what you are doing.
 #
 # Please note that environment variables take precedence over the config file.