New cop that detects foreign key-like columns with incorrect types

[fatkodima]

Fortunately, rails since 5.1 adds foreign key columns (like post_id) with bigint types (or the type explicitly configured by the application). This works implicitly when adding them by add_reference helper. But people sometimes add columns via add_column or t.column or t.integer, so this can lead to incorrect (like integer) types columns. I saw a couple of offences in my application.

I want to propose a cop that detects such cases based on the configured type (bigint by default), but can be configured via some cop's option.

@koic Are you open for this?