[documentation] Be a little bit verbose with aliases and setup

doc/cookbook/aliased-indexes.md

@@ -18,32 +18,84 @@ fos_elastica:
 ```
 
 The process for setting up aliases on an existing application is slightly more complicated
-because the bundle is not able to set an alias as the same name as an index. You have some
+because the bundle is not able to set an alias as the same name as an index. You have 2
 options on how to handle this:
 
-1) Delete the index from Elasticsearch. This option will make searching unavailable in your
+1) Option with downtime : Delete the index from Elasticsearch. This option will make searching unavailable in your
    application until a population has completed itself, and an alias is created.
 
 ```bash
 $ curl -XDELETE 'http://localhost:9200/app/'
 ```
 
-2) Change the index_name parameter for your index to something new, and manually alias the
+2) Option without downtime : Change the index_name parameter for your index to something new, and manually alias the
    current index to the new index_name, which will then be replaced when you run a repopulate.
 
+```bash
+# before actions
+curl -XGET 'http://localhost:9200/_alias/?pretty'
+{
+  "app" : {
+    "aliases" : { }
+  }
+}
+
+# create alias to switch after with no downtime
+$ curl -XPOST 'http://localhost:9200/_aliases' -H 'Content-Type: application/json'  -d '
+{
+    "actions" : [
+        { "add" : { "index" : "app", "alias" : "app_prod" } }
+    ]
+}'
+
+#check alias is ok
+curl -XGET 'http://localhost:9200/_alias/?pretty'
+{
+  "app" : {
+    "aliases" : { "app_prod" : { } }
+  }
+}
+
+```
+
 ```yaml
+#index name is alias name
 fos_elastica:
     indexes:
         app:
             use_alias: true
             index_name: app_prod
 ```
 
+clear caches etc, now fos use alias instead of index
 ```bash
-$ curl -XPOST 'http://localhost:9200/_aliases' -H 'Content-Type: application/json' -d '
+bin/console -eprod 'fos:elastica:populate'
+```
+in other cli in // check indexes during populate process
+```bash
+curl -XGET 'http://localhost:9200/_alias/?pretty'
 {
-    "actions" : [
-        { "add" : { "index" : "app", "alias" : "app_prod" } }
-    ]
-}'
+  "app" : {
+    "aliases" : {
+      "app_prod" : { }
+    }
+  },
+  "app_prod_2019-05-28-153852" : {
+    "aliases" : { }
+  }
+}
+
+```
+when 'fos:elastica:populate' command finish
+
+```bash
+curl -XGET 'http://localhost:9200/_alias/?pretty'
+{
+  "app_prod_2019-05-28-153852" : {
+    "aliases" : {
+        "app_prod" : { }
+    }
+  }
+}
+
 ```