Docs about mongodb migration usage adjusted

Author: klimov-paul

extensions/mongodb/CHANGELOG.md

@@ -7,7 +7,7 @@ Yii Framework 2 mongodb extension Change Log
 - Bug #3385: Fixed "The 'connected' property is deprecated" (samdark)
 - Enh #3520: Added `unlinkAll()`-method to active record to remove all records of a model relation (NmDimas, samdark, cebe)
 - Enh #3778: Gii generator for Active Record model added (klimov-paul)
-- Enh: Migration support added (klimov-paul)
+- Enh #3947: Migration support added (klimov-paul)
 
 
 2.0.0-beta April 13, 2014

extensions/mongodb/README.md

@@ -285,4 +285,38 @@ return [
 ```
 
 > Note: since MongoDB is schemaless, there is not much information, which generated code may base on. So generated code
-  is very basic and definitely requires adjustments.
+  is very basic and definitely requires adjustments.
+
+
+Using Migrations
+----------------
+
+MongoDB is schemaless and will create any missing collection on the first demand. However there are many cases, when
+you may need applying persistent changes to the MongoDB database. For example: you may need to create a collection with
+some specific options or create indexes.
+MongoDB migrations are managed via [[yii\mongodb\console\controllers\MigrateController]], which is an analog of regular
+[[\yii\console\controllers\MigrateController]].
+
+In order to enable this command you should adjust the configuration of your console application:
+
+```php
+return [
+    // ...
+    'controllerMap' => [
+        'mongodb-migrate' => 'yii\mongodb\console\controllers\MigrateController'
+    ],
+];
+```
+
+Below are some common usages of this command:
+
+```
+# creates a new migration named 'create_user_collection'
+yii mongodb-migrate/create create_user_collection
+
+# applies ALL new migrations
+yii mongodb-migrate
+
+# reverts the last applied migration
+yii mongodb-migrate/down
+```

extensions/mongodb/console/controllers/MigrateController.php

@@ -17,7 +17,7 @@
 /**
  * Manages application MongoDB migrations.
  *
- * This is an analog of [[\yii\console\controllers|MigrateController]] for MongoDB.
+ * This is an analog of [[\yii\console\controllers\MigrateController]] for MongoDB.
  *
  * This command provides support for tracking the migration history, upgrading
  * or downloading with migrations, and creating new migration skeletons.
@@ -40,8 +40,8 @@
  * Below are some common usages of this command:
  *
  * ~~~
- * # creates a new migration named 'create_user_table'
- * yii mongodb-migrate/create create_user_table
+ * # creates a new migration named 'create_user_collection'
+ * yii mongodb-migrate/create create_user_collection
  *
  * # applies ALL new migrations
  * yii mongodb-migrate