I implemented Foreign key create in `create_table` for SQLite3 at
#24743. This follows #24743 to implement `add_foreign_key` and
`remove_foreign_key`.
Unfortunately SQLite3 has one limitation that
`PRAGMA foreign_key_list(table-name)` doesn't have constraint name.
So we couldn't implement find/remove foreign key by name for now.
Fixes#35207.
Closes#31343.
In MySQL, the text column size is 65,535 bytes by default (1 GiB in
PostgreSQL). It is sometimes too short when people want to use a text
column, so they sometimes change the text size to mediumtext (16 MiB) or
longtext (4 GiB) by giving the `limit` option.
Unlike MySQL, PostgreSQL doesn't allow the `limit` option for a text
column (raises ERROR: type modifier is not allowed for type "text").
So `limit: 4294967295` (longtext) couldn't be used in Action Text.
I've allowed changing text and blob size without giving the `limit`
option, it prevents that migration failure on PostgreSQL.
Failing test before the ActionText::RichText change:
```
Error:
ActionText::ModelTest#test_embed_extraction_only_extracts_file_attachments:
ArgumentError: Could not find or build blob: expected attachable, got #<ActionText::Attachables::RemoteImage:0x00007fb0259fef70 @url="http://example.com/cat.jpg", @content_type="image", @width=nil, @height=nil>
```
- config.load_defaults 6.0 in the dummy app and
fix the test since by default rails 6.0 configured
does not generate "utf8" hidden input, see #32125
- Use `ActiveRecord::Migration[6.0]` in the dummy app
since actiontext will be since Rails 6.0
- Fix `CreateActiveStorageTables` migration in the dummy app.
Add `t.foreign_key :active_storage_blobs, column: :blob_id`
It was added in 2ae3a29508.
- `rails/actiontext$ yarn install`
