module ActiveSupport::Inflector

downcase_first('') # => ""
downcase_first('I') # => "i"
downcase_first('If they enjoyed The Matrix') # => "if they enjoyed The Matrix"

Converts the first character in the string to lowercase.

def downcase_first(string)
  string.length > 0 ? string[0].downcase.concat(string[1..-1]) : +""
end