* Fixed some offenses
* Added test.

Fixed some offenses

* Fixed Posgresql index tables with `public`.

Added indexes test.

Added test not crash getting indexes.

* Updated rake and rubocop.

Ruby 2.4.0 unifies Fixnum and Bignum into Integer.

https://bugs.ruby-lang.org/issues/12005

Fix following deprecated warnings in Ruby 2.4.0-preview3.

- `warning: constant ::Fixnum is deprecated`
- `warning: constant ::Bignum is deprecated`

use existence of 'Rails::Application' as indicator of Rails App instead of 'Rails', as many Ruby applications are using railties such as generators outside Rails

* add(annotate_models_spec): test coverage
* change(annotate_models#get_foreign_key_info): elide auto-generated fk names

Closes #404.

* Provide :hide_default_column_types option to make hiding of default configurable

* Use `NO_DEFAULT_COL_TYPES` as default when the `hide_default_column_types` option is not provided

* add option to exclude STI subclasses from annotation

The fatal error was introduced with commit fc31d85. The method
`supports_foreign_keys?` is only available on ActiveRecord versions
>= 4.2.

Fixes issue 316.

 - Replace SpaceAroundKeyword with SpaceAfterControlKeyword
 - Use an explicit rubocop version to avoid breakages during PRs

Annotate should reset the cached information about columns because Annotate may output old information if we load ActiveRecord::Base class in migration files.

For example, if we have a following migration file and execute 'rake db:migrate', Annote does not output the default value and a not null constraint of the `some_value` column.

```ruby
class CreatePosts < ActiveRecord::Migration
  def change
    create_table :posts do |t|
      t.integer :some_value
    end

    # add a not null constraint to the some_value column

    # should update some_value with not null values
    # because records might exist which have null value in the some_value column

    Post.update_all(some_value: 1)

    change_column_null(:posts, :some_value, false)
    change_column_default(:posts, :some_value, 1)
  end
end
```

This commit fixes the above issue.

Reduced the Cyclomatic complexity.
#330 By default didn't annotate activeadmin models.
This close #330

Added coveralls and code climate gems.

Do not annotate controllers, helpers and scaffolds by default (revert to behavior from previous version)