#from_hash in the HashConverter does not accept HashWithIndifferentAccess data type

[bghalami-rc]

There are inconsistencies with how Ruby on Rails and how this gem interpret what is and what isn't a valid Hash which trigger the argument error in the hash_converter.rb

pry(main)> ActiveSupport::HashWithIndifferentAccess.new({}).is_a?(Hash)
=> true
pry(main)> children = ActiveSupport::HashWithIndifferentAccess.new({})
=> {}
pry(main)> [Hash, NilClass].include?(children.class)
=> false

Example

[33] pry(main)> test_arr = [
  {
    title: 'string hash (indifferent, new key, hash value)',
    hash: { 'key' => nil }.with_indifferent_access.tap do |h|
      h['key2'] = { 'key3' => nil }
    end
  }
]
=> [{:title=>"string hash (indifferent, new key, hash value)", :hash=>{"key"=>nil, "key2"=>{"key3"=>nil}}}]

[34] pry(main)> test_arr.each do |test|
  puts test[:title]
  puts JSON.pretty_generate(test[:hash])
  Tree::TreeNode.new(:root).tap do |tree|
    tree.add_from_hash(sorted_hash_for_tree_load(test[:hash]))
  end.print_tree; 0
rescue => e
  puts e.message
string hash (indifferent, new key, hash value)
{
  "key": null,
  "key2": {
    "key3": null
  }
}
Invalid child. Must be nil or hash.
=> [{:title=>"string hash (indifferent, new key, hash value)", :hash=>{"key"=>nil, "key2"=>{"key3"=>nil}}}]