Changed the "level" column in "log" table to be integer again

[Dzhuneyt]

Q	A
Is bugfix?	yes
New feature?	no
Breaks BC?	no
Tests pass?	yes
Fixed issues	https://github.com/yiisoft/yii-core/issues/132

[samdark]

How about making it a single migration? We can do that since there were no package releases yet.

[Dzhuneyt]

@samdark what about customers that upgrade from an older version of Yii? They will have the old migration already executed and the column type the wrong one.

[samdark]

There is no compatibility guarantee between Yii 2.0 and Yii 3.0. But if you think that two separate migrations are better, I'm fine with it.

[samdark]

Merged. Thanks!

[Dzhuneyt]

There is no compatibility guarantee between Yii 2.0 and Yii 3.0. But if you think that two separate migrations are better, I'm fine with it.

I have bad experiencing changing old migrations' code for ANY reason in my day job. That's all :)

[Dzhuneyt]

@samdark just out of curiousity, now that a lot of functionalities have been moved outside of the yii-core project into their own dedicated projects - will they all have their own CHANGELOG file (I see this one doesn't, for example).

[samdark]

Yes. After first release.