* Prevent root_dir option from being empty

When setting root_dir to an empty string (as is done in the default rake
task config) this line previously caused root_dir to become an empty
array.

This in turn caused factories, specs etc not to be annotated.

This is just a quick band-aid on a larger problem. We have option
parsing spread out over many different places, with slight mismatches
like this in the assumptions made.

* Handle blank values & comma-separated strings in AnnotateModels.root_dir

These cases are currently handled (inconsistently) in the different
option parsing routines.

* Pass root_dir forward unmodified

The different cases are now handled inside AnnotateModels

* Add ruby 2.4 for travis

Do not check if an index includes another column if the name is a String, instead of an Array. (#442)

* Do not check if an index includes another column if the name is a String, instead of an Array.

* Fix Rubocop test conditions.

* --active-admin replaced as a flag.
closes #363.

* Implemented routes in markdown, closes #178

* Fix code style offenses + tests

* Fixed some offenses
* Added test.

Fixed some offenses

* Added new gems.

* 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.

* Correct 'comas' to 'commas' in README

* 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

Fix configuration in rails README link

Annotate should reset the cached information about columns