Add ability to destroy a user with 0 posts

lib/user_destroyer.rb

@@ -0,0 +1,27 @@
+require_dependency 'admin_logger'
+
+# Responsible for destroying a User record
+class UserDestroyer
+
+  class PostsExistError < RuntimeError; end
+
+  def initialize(admin)
+    @admin = admin
+    raise Discourse::InvalidParameters.new('admin is nil') unless @admin and @admin.is_a?(User)
+    raise Discourse::InvalidAccess unless @admin.admin?
+  end
+
+  # Returns false if the user failed to be deleted.
+  # Returns a frozen instance of the User if the delete succeeded.
+  def destroy(user)
+    raise Discourse::InvalidParameters.new('user is nil') unless user and user.is_a?(User)
+    raise PostsExistError if user.post_count != 0
+    user.destroy.tap do |u|
+      if u
+        AdminLogger.new(@admin).log_user_deletion(user)
+        MessageBus.publish "/file-change", ["refresh"], user_ids: [user.id]
+      end
+    end
+  end
+
+end