add active model basics wip to guides/documents.yaml
support :unless_exist for FileCache
added schema_migrations_table_name to ActiveRecord::Base in order that the name of the schema migrations table can be configured.

consolidated test_schema_migrations_table_name tests

Added changelog entry

edited changelog

removed commented lines

removed reader

ensure the schema migrations table is reset at end of test

added entry to configuration guide

guides typo and changelog order
Assert the return value in the test
Remove warning of shadowing outer local variable
Fixed tests for app_generator

Added test for jbuilder and web-console inclusion.

Added README.rdoc for test default files
Merge pull request #12668 from arunagw/aa-improvments

Test fixed for app_generator
Merge pull request #12578 from jeradphelps/configurable_schema_migrations_table_name

Configurable name for schema_migrations table

Conflicts:
	activerecord/CHANGELOG.md
Fix indentation [ci skip]
Fix typo
fix typo in comment [ci skip].
Merge pull request #11564 from zzak/active_model_guide

[Guides] Active Model Basics [ci skip]
use a queue rather than a list. fixes #12069
Merge pull request #11785 from grosser/grosser/file-unless-exist

support :unless_exist for FileCache

Conflicts:
	activesupport/CHANGELOG.md
	activesupport/test/caching_test.rb
always call set_default_accessors from create_root
fix template Gemfiles
Remove confusing generated-code commentary
Add failing test for preloading with a polymorphic association and using the existential predicate
Fix broken delete_all test, which will now be failing since #delete_all is broken
Result should return type_casted values

The `type_cast` should be done earlier. `select_*` uses the values
provided by the `result` class, so it makes sense to use the `type_cast`
method from the adapters and passed into the class (`column_types`).

*before*

```
Person.create(
  tags: ["cfabianski", "cedric"],
  tag_ids: [4, 8, 9]
)

query = Person.where(["? = ANY (tags)", "cfabianski"])
row   = Person.connection.select_one(query)

=> {"id" => "1", tags" => "{cfabianski,cedric}", "tag_ids" => "{4,8,9}"}
```

*after*

```
Person.create(
  tags: ["cfabianski", "cedric"],
  tag_ids: [4, 8, 9]
)

query = Person.where(["? = ANY (tags)", "cfabianski"])
row   = Person.connection.select_one(query)

=> {"id" => 1, "tags" => [cfabianski, cedric], "tag_ids" => [4, 8, 9]}
```