elasticsearch_settings.yml

analysis:
  filter:
    ngrams:
      side: front
      max_gram: 10
      min_gram: 1
      type: edgeNGram
  analyzer:
    full:
      tokenizer: standard
      filter: ["standard", "lowercase", "asciifolding", "trim"]
      type: custom
    partial:
      tokenizer: standard
      filter: ["standard", "lowercase", "asciifolding", "ngrams", "trim"]
      type: custom

model.rb

  settings ElasticSearchAnalysis do
    mapping do
      indexes :name, type: 'multi_field', fields: {
        name: {type: 'string', analyzer: 'full', boost: 3},
        partial: {type: 'string', search_analyzer: 'full', index_analyzer: 'partial'}
      }
    end
  end