Add term query doc.

docs/Query/Term.md

+# Term Query
+
+> More info about term query is in the [official elasticsearch docs][1]
+
+The term query finds documents that contain the exact term specified in the inverted index.
+
+
+## Simple example
+
+```JSON
+{
+    "term" : { "user" : "Kimchy" } 
+}
+```
+
+In DSL:
+
+```php
+$termQuery = new TermQuery('user', 'Kimchy');
+
+$search = new Search();
+$search->addQuery($termQuery);
+
+$queryArray = $search->toArray();
+```
+
+[1]: https://www.elastic.co/guide/en/elasticsearch/reference/current/query-dsl-term-query.html