Allow disabling S3 explicitly, disable in Docker Compose

For example when there is a .env.development for running the app on a
host machine directly, but as a developer you also want to run it with
Docker Compose from time to time.

config/environments/development.rb

@@ -71,7 +71,7 @@ Rails.application.configure do
   # Allow requests from any IP
   config.web_console.permissions = '0.0.0.0/0'
 
-  if ENV["S3_ENABLED"]
+  if ENV["S3_ENABLED"] && ENV["S3_ENABLED"].to_s != "false"
     config.active_storage.service = :s3
   else
     config.active_storage.service = :local

config/environments/production.rb

@@ -110,7 +110,7 @@ Rails.application.configure do
   # Set this to true and configure the email server for immediate delivery to raise delivery errors.
   config.action_mailer.raise_delivery_errors = true
 
-  if ENV["S3_ENABLED"]
+  if ENV["S3_ENABLED"] && ENV["S3_ENABLED"].to_s != "false"
     config.active_storage.service = :s3
   else
     config.active_storage.service = :local

config/storage.yml

@@ -6,7 +6,7 @@ test:
   service: Disk
   root: <%= Rails.root.join("tmp/storage") %>
 
-<% if ENV["S3_ENABLED"] %>
+<% if ENV["S3_ENABLED"] && ENV["S3_ENABLED"].to_s != "false" %>
 s3:
   service: S3
   endpoint: <%= ENV["S3_ENDPOINT"] %>