Why don't we add an index to the version column and modify the TaskRecord.completed_task? method as shown below, to make it more efficient?

from:

def self.completed_task?(version)
  all.any?{|t| t.version == version}
end

to:

def self.completed_task?(version)
  exists?(version: version)
end

This is way more efficient when you use it for a while and have lots of tasks there.

BTW, the uniqueness of version field should be enforced.