Update README.md

README.md

@@ -8,6 +8,8 @@ To install on your current ES node, use the plugin binary provided in the bin fo
 
 ## Usage
 The plugin provides a token filter of type `concatenate` which has one parameter `token_separator`. Use it in your custom analyzers to merge tokenized strings back into one single token (usually after applying stemming or other token filters).
+### Arrays
+When saving arrays of strings to a field, these are handled in elasticsearch as separate tokens, so this filter would collapse all the elements of the array into one, and usually you don't want that to happen. As a workaround you can set `position_offset_gap` on the field to a high number and pass the same number as the `increment_gap` parameter to the filter, which then only concatenates all tokens closer than this value.
 
 ## Example
 Given the custom analyzer (see https://www.elastic.co/guide/en/elasticsearch/guide/current/custom-analyzers.html):