Git workshop rails by senny

1: git log -S auto_explain_threshold_in_seconds --reverse
2: git log -1 0306f82e0c3cda3aad1b45eb0c3a359c254b62cc --format=fuller
3: git tag --contains 0306f82e0c3cda3aad1b45eb0c3a359c254b62cc -l | grep 'v' | head -n 1
4: git tag --contains d3688e0 -l | grep 'v' | head -n 1
5: activerecord/lib/active_record/explain.rb
6: git log --pretty=format:%an --follow activerecord/lib/active_record/explain.rb | sort | uniq
7: 'We discussed that the auto explain feature is rarely used.
    This PR removes only the automatic explain. You can still display
    the explain output for any given relation using `ActiveRecord::Relation#explain`.

    As a side-effect this should also fix the connection problem during
    asset compilation (#9385). The auto explain initializer in the `ActiveRecord::Railtie`
    forced a connection.'
8: @fxn, @senny, @rafaelfranca
9: git log --oneline --stat -S auto_explain_threshold_in_seconds -- guides/ | grep '|' | cut -d"|" -f1 | cut -d" " -f2 | sort | uniq
10:

1:  7424cbb changelog entry
    c0554f1 we need to require the code :S
    58081ac length validator
    122d721 added test to reproduce
    3431717 move files

2:  80bdb82 length validator, require code, changelog entry
    122d721 added test to reproduce
    3431717 move files

3:  0f3c796 length validator and patch implementation
    3431717 move files

    def test_validates_size_of_association_utf8
      assert_nothing_raised { Owner.validates_size_of :pets, minimum: 1 }
      o = Owner.new(name: 'あいうえおかきくけこ')
      assert !o.save
      assert o.errors[:pets].any?
      o.pets.build(name: 'あいうえおかきくけこ')
      assert o.valid?
    end