Skeletton for the ES documentation

docs/components/off-the-shelf-apps/elasticsearch.md

+# Elasticsearch
+
+## Data storage
+
+## Multiple indexes
+
+- [metadata and data](../indexers/metadata-and-data.md)
+- [editorial content from Ghost](../indexers/editorial-content.md): posts and pages
+
+## How the content is used
+
+### Search
+
+### Autocompletion
+
+### Suggestion
+
+### Editorial content
+
+## Aliases strategy
+
 Quid de la couche AUTHZ ?
+
+## Multiple instances