Private visibility on statuses prevents non-followers from seeing those

Filters out hidden stream entries from Atom feed
Blocks now generate hidden stream entries, can be used to federate blocks
Private statuses cannot be reblogged (generates generic 422 error for now)
POST /api/v1/statuses now takes visibility=(public|unlisted|private) param instead of unlisted boolean
Statuses JSON now contains visibility=(public|unlisted|private) field

app/models/block.rb

@@ -1,9 +1,31 @@
 # frozen_string_literal: true
 
 class Block < ApplicationRecord
+  include Streamable
+
   belongs_to :account
   belongs_to :target_account, class_name: 'Account'
 
   validates :account, :target_account, presence: true
   validates :account_id, uniqueness: { scope: :target_account_id }
+
+  def verb
+    destroyed? ? :unblock : :block
+  end
+
+  def target
+    target_account
+  end
+
+  def object_type
+    :person
+  end
+
+  def hidden?
+    true
+  end
+
+  def title
+    destroyed? ? "#{account.acct} is no longer blocking #{target_account.acct}" : "#{account.acct} blocked #{target_account.acct}"
+  end
 end