title: Extract properties from indexed data in elasticsearch
body: <p>I have trouble understanding the possibilities of tokenizers and analyzers in Elasticsearch.</p>
  
  <p>Suppose there is a set of indexed data of products. Each product has a field with a description text. In the description a color is named.</p>
  
  <p>Is it possible to use one of the built in analyzers or a custom tokenizer/analyzer to extract that color information (eg. based on a set of keywords [red,green,blue,yellow etc.]) and attach that new color information as a separate field to the product?</p>
  
  <p>Would be a nice feature to augment incoming data with generic properties (eg. colors, material etc.)</p>