Update Mastodon Redis config

They introduced Redis URLs for the config, so I removed our own
additions and added the URL.

site-cookbooks/kosmos-mastodon/attributes/default.rb

@@ -2,3 +2,4 @@ node.default["kosmos-mastodon"]["directory"]      = "/opt/mastodon"
 node.default["kosmos-mastodon"]["puma_port"]      = 3000
 node.default["kosmos-mastodon"]["streaming_port"] = 4000
 node.default["kosmos-mastodon"]["server_name"]    = "kosmos.social"
+node.default["kosmos-mastodon"]["redis_url"]      = "redis://localhost:6379/1"

site-cookbooks/kosmos-mastodon/recipes/default.rb

@@ -71,8 +71,7 @@ application mastodon_path do
     mode  "0640"
     owner "mastodon"
     group "mastodon"
-    variables redis_db: 1,
-              redis_actioncable_db: 2,
+    variables redis_url: node["kosmos-mastodon"]["redis_url"],
               domain: node["kosmos-mastodon"]["server_name"],
               paperclip_secret: mastodon_credentials['paperclip_secret'],
               secret_key_base: mastodon_credentials['secret_key_base'],

site-cookbooks/kosmos-mastodon/templates/default/env.production.erb

@@ -1,8 +1,5 @@
 # Service dependencies
-REDIS_HOST=localhost
-REDIS_PORT=6379
-REDIS_DB=<%= @redis_db %>
-REDIS_ACTIONCABLE_DB=<%= @redis_actioncable_db %>
+REDIS_URL=<%= @redis_url %>
 DB_HOST=localhost
 DB_USER=postgres
 DB_NAME=mastodon