v4.0.1

Bugfixes:

• ab_test must return metadata on error or if split is disabled/excluded user (@andrehjr, #622)
• Fix versioned experiments when used with allow_multiple_experiments=control (@andrehjr, #613)
• Only block Pinterest bot (@huoxito, #606)
• Respect experiment defaults when loading experiments in initializer. (@mattwd7, #599)
• Removes metadata key when it updated to nil (@andrehjr, #633)
• Force experiment does not count for metrics (@andrehjr, #637)
• Fix cleanup_old_versions! misbehaviour (@serggl, #661)

Features:

• Make goals accessible via on_trial_complete callbacks (@robin-phung, #625)
• Replace usage of SimpleRandom with RubyStats(Used for Beta Distribution RNG) (@andrehjr, #616)
• Introduce enable/disable experiment cohorting (@robin-phung, #615)
• Add on_experiment_winner_choose callback (@GenaMinenkov, #574)
• Add Split::Cache to reduce load on Redis (@rdh, #648)
• Caching based optimization in the experiment#save path (@amangup, #652)
• Adds config option for cookie domain (@joedelia, #664)

Misc:

• Drop support for Ruby < 2.5 (@andrehjr, #627)
• Drop support for Rails < 5 (@andrehjr, #607)
• Bump minimum required redis to 4.2 (@andrehjr, #628)
• Removed repeated loading from config (@robin-phung, #619)
• Simplify RedisInterface usage when persisting Experiment alternatives (@andrehjr, #632)
• Remove redis_url impl. Deprecated on version 2.2 (@andrehjr, #631)
• Remove thread_safe config as redis-rb is thread_safe by default (@andrehjr, #630)
• Fix typo of in Split::Trial class variable (TomasBarry, #644)
• Single HSET to update values, instead of multiple ones (@andrehjr, #640)
• Use Redis#hmset to keep compatibility with Redis < 4.0 (@andrehjr, #659)
• Remove 'set' parsing for alternatives. Sets were used as storage and deprecated on 0.x (@andrehjr, #639)
• Adding documentation related to what is stored on cookies. (@andrehjr, #634)
• Keep railtie defined under the Split gem namespace (@avit, #666)
• Update RSpec helper to support block syntax (@clowder, #665)