update readme file

Author: nekufa

README.md

@@ -6,3 +6,191 @@
 [![Scrutinizer Code Quality](https://scrutinizer-ci.com/g/tarantool-php/mapper/badges/quality-score.png?b=master)](https://scrutinizer-ci.com/g/tarantool-php/mapper/?branch=master)
 [![Code Coverage](https://scrutinizer-ci.com/g/tarantool-php/mapper/badges/coverage.png?b=master)](https://scrutinizer-ci.com/g/tarantool-php/mapper/?branch=master)
 
+Install using composer.
+```json
+{
+  "require": {
+    "tarantool/mapper": "^2.0.0"
+  }
+}
+```
+
+# Instantiate manager
+Usually, you manage dependencies in your service provider.
+To get started you should instantiate connection, packer, client and manager itself.
+In this example we use PurePacker and StreamConnection. It means you don't need any pecl extensions. To see other implementations please check [client documentation](https://github.com/tarantool-php/client#usage)
+
+```php
+use Tarantool\Client\Client;
+use Tarantool\Client\Connection\StreamConnection;
+use Tarantool\Client\Packer\PurePacker;
+use Tarantool\Mapper\Manager;
+
+$connection = new StreamConnection();
+$client = new Client($connection, new PurePacker());
+$mapper = new Mapper($client);
+```
+
+# Logging
+By default, client does not logs tarantool requests, you can use mapper\client that supports logging.
+```php
+use Tarantool\Client\Connection\StreamConnection;
+use Tarantool\Client\Packer\PurePacker;
+use Tarantool\Mapper\Manager;
+use Tarantool\Mapper\Client;
+
+$connection = new StreamConnection();
+$client = new Client($connection, new PurePacker());
+$mapper = new Mapper($client);
+
+$result = $client->ping();
+
+$log = $client->getLog();
+```
+
+# Describe entities
+To get started you should describe your types and fields using meta object.
+```php
+
+$person = $mapper->getSchema()->createSpace('person');
+
+// add properties
+$person->addProperty('id', 'unsigned');
+$person->addProperty('name', 'str');
+$person->addProperty('birthday', 'unsigned');
+$person->addProperty('gender', 'str');
+
+// add indexes
+// first index is primary
+$person->createIndex([
+    'type' => 'hash', // define type
+    'fields' => ['id'],
+]);
+
+// create unique indexes using property or array of properties as parameter
+$person->createIndex('name');
+
+// create not unique indexes
+$person->createIndex([
+    'fields' => 'birthday',
+    'unique' => false
+]);
+
+// if you wish - you can specify index name
+$person->createIndex([
+    'fields' => ['name', 'birthday'],
+    'type' => 'hash',
+    'name' => 
+]);
+```
+
+# Working with the data
+Now you can store and retreive data from tarantool storage using mapper instance.
+```php
+// get repository instance
+$persons = $mapper->getRepository('person');
+
+// create new entity
+$dmitry = $persons->create([
+  'id' => 1,
+  'name' => 'Dmitry'
+]);
+
+// save
+$mapper->save($dmitry);
+
+// you can create entities using manager wrapper.
+// this way entity will be created and saved in the tarantool
+$vasily = $mapper->create('person', [
+  'id' => 2,
+  'name' => 'Vasily'
+]);
+
+// you can retreive entites by id from repository
+$helloWorld = $mapper->getRepository('post')->find(3);
+
+// or using manager wrapper
+$helloWorld = $mapper->find('post', 3);
+
+// updates are easy
+$helloWorld->title = "Hello World!";
+$mapper->save($helloWorld);
+```
+# Indexes
+```php
+$note = $mapper->getSchema()->createSpace('note');
+$note->addProperty('slug', 'str');
+$note->addProperty('title', 'str', 
+$note->addProperty('status', 'str');
+
+$note->addIndex('slug');
+$note->addIndex([
+  fields' => 'status',
+  'unique' => false
+]);
+
+// find using repository
+$mapper->getRepository('note')->find(['status' => 'active']);
+// find using shortcut
+$mapper->find('note', ['status' => 'active']);
+
+// find first
+$mapper->getRepository('note')->findOne(['slug' => 'my-secret-note']);
+
+// composite indexes can be used partial
+$person = $mapper->getSchema()->createSpace('person');
+$person->addProperty('id', 'unsigned');
+$person->addProperty('client', 'unsigned');
+$person->addProperty('sector', 'unsigned');
+$person->addProperty('name', 'unsigned');
+
+$person->addIndex('id');
+$person->addIndex([
+  'fields' => ['client', 'sector'],
+  'unique' => false
+]);
+
+// using index parts
+$mapper->find('person', ['client' => 2]);
+$mapper->find('person', ['client' => 2, 'sector' => 27]);
+```
+
+# Array properties
+You can store arrays as property without any serialization to string.
+```php
+$pattern = $mapper->getSchema()->createSpace('shift_pattern'); 
+$pattern->addProperty('id', 'unsigned');
+$pattern->addProperty('title', 'str');
+$pattern->addProperty('pattern', '*');
+
+$pattern->addIndex('id');
+
+$mapper->create('shift_pattern', [
+  'id' => 1,
+  'title' => '5 days week',
+  'pattern' => [
+    ['work' => true],
+    ['work' => true],
+    ['work' => true],
+    ['work' => true],
+    ['work' => true],
+    ['work' => false],
+    ['work' => false],
+  ]
+]);
+
+$mapper->get('shift_pattern', 1)->pattern[5]; // read element with index 5 from pattern array
+```
+
+# Internals
+Mapper uses IdentityMap and query caching
+```php
+$dmitry = $mapper->getRepository('person')->findOne(['name' => 'Dmitry']); // person with id 1
+echo $dmitry == $mapper->findOne('person', 1); // true
+
+// query result are cached until you create new entites
+$mapper->getRepository('person')->findOne(['name' => 'Dmitry']);
+
+// you can flush cache manually
+$mapper->getRepository('person')->flushCache();
+```