Hi there. I've been experimenting with the search templates recently and I'm a bit confused. Shouldn't the Mustache tags be written like `{{tagname}}` instead of `{tagname}`? Your using `{{...}}` [here](http://www.elastic.co/guide/en/elasticsearch/reference/current/search-template.html) BTW.
Using the first example in that page seems to indicate that something's wrong, or am I missing something?
```
$ curl 'localhost:9200/test/_search' -d '{"query":{"template":{"query":{"match":{"text":"{keywords}"}},"params":{"keywords":"value1_foo"}}}}'
{"took":1,"timed_out":false,"_shards":{"total":1,"successful":1,"failed":0},"hits":{"total":0,"max_score":null,"hits":[]}}
$ curl 'localhost:9200/test/_search' -d '{"query":{"template":{"query":{"match":{"text":"{{keywords}}"}},"params":{"keywords":"value1_foo"}}}}'
{"took":1,"timed_out":false,"_shards":{"total":1,"successful":1,"failed":0},"hits":{"total":1,"max_score":1.0,"hits":[{"_index":"test","_type":"testtype","_id":"1","_score":1.0,"_source":{"text":"value1_foo"}}]}}
```
Adds support for storing mustache based query templates that can later be filled
with query parameter values at execution time. Templates may be both quoted,
non-quoted and referencing templates stored in config/scripts/*.mustache by file
name.
See docs/reference/query-dsl/queries/template-query.asciidoc for templating
examples.
Implementation detail: mustache itself is being shaded as it depends directly on
guava - so having it marked optional but included in the final distribution
raises chances of version conflicts downstream.
Fixes#4879
navins
Oliver Eilhard
Clinton Gormley
Brian Murphy
bleskes
Alexander Reelsen
Isabel Drost-Fromm