add customer api

doc/upgrade.txt

@@ -0,0 +1,23 @@
+composer self-update
+
+## composer --version
+## Do not run Composer as root/super user! See https://getcomposer.org/root for details
+## Composer version 1.9.0 2019-08-02 20:55:32
+
+
+composer config -g github-oauth.github.com 4fe4faf52ce29b298d02c6473a1ee7e10047ed7c
+
+#token: 4fe4faf52ce29b298d02c6473a1ee7e10047ed7c
+
+composer require "fxp/composer-asset-plugin:^1.1.3"
+
+composer require "fxp/composer-asset-plugin:dev-master"
+
+# composer require "yiisoft/yii2":"2.0.7"
+
+# sometimes it works only, if we first update to this version and then to the higher version
+composer require "yiisoft/yii2":"2.0.5"
+
+composer require "yiisoft/yii2:~2.0.10" --update-with-dependencies
+
+