fixup! added upgrade instructions for adding backend API to existing …

…project

docs/upgrade/UPGRADE-v8.0.0.md

@@ -70,7 +70,7 @@ There you can find links to upgrade notes for other versions too.
             + use FOS\CKEditorBundle\Form\Type\CKEditorType;
             ```
 - update the minimal PHP version in your `composer.json` in `require` and `config.platform` section to `7.2` because version `7.1` is no longer supported in Shopsys Framework ([#1066](https://github.com/shopsys/shopsys/pull/1066))
-- follow instructions in [the separate article](upgrade-instructions-for-backend-api.md) to introduce backend API into your project ([#1055](https://github.com/shopsys/shopsys/pull/1055))
+- if you want to use our experimental API follow these instructions in [the separate article](upgrade-instructions-for-backend-api.md) to introduce backend API into your project ([#1055](https://github.com/shopsys/shopsys/pull/1055))
     - we recommend to read [introduction to backend API](/docs/backend-api/introduction-to-backend-api.md) article as well
 
 ### Configuration

docs/upgrade/upgrade-instructions-for-backend-api.md

@@ -24,7 +24,7 @@ To start using the backend API, follow the instructions (you can also find inspi
                 - { path: '^/api', prefer_extension: true, fallback_format: 'json', priorities: [ 'json', 'xml' ] }
                 - { path: '^/', stop: true }
     ```
-- create configuration for Trikoder OAuth bundle in `app/config/packages/trikoder_oauth2.yml`
+- create configuration for Trikoder OAuth2 bundle in `app/config/packages/trikoder_oauth2.yml`
     ```yaml
     trikoder_oauth2:
         authorization_server:
@@ -47,7 +47,7 @@ To start using the backend API, follow the instructions (you can also find inspi
             doctrine:
                 entity_manager: default
     ```
-- create configuration for OAuth keys and parameters
+- create configuration for OAuth2 keys and parameters
     - create directory `app/config/packages/oauth2`
     - create `app/config/packages/oauth2/.gitignore` as private keys must not be ever pushed
         ```
@@ -100,7 +100,7 @@ To start using the backend API, follow the instructions (you can also find inspi
     +     new Shopsys\BackendApiBundle\ShopsysBackendApiBundle(),
     +     new Trikoder\Bundle\OAuth2Bundle\TrikoderOAuth2Bundle(),
     ```
-    and loading of OAuth parameters
+    and loading of OAuth2 parameters
     ```diff
     if (file_exists(__DIR__ . '/config/parameters_version.yml')) {
         $configs[] = __DIR__ . '/config/parameters_version.yml';
@@ -111,4 +111,4 @@ To start using the backend API, follow the instructions (you can also find inspi
     + }
     ```
 - run [db-create](/docs/introduction/console-commands-for-application-management-phing-targets.md#db-create) (this one even on production) and `test-db-create` phing targets to install extension for UUID
-- run [backend-api-oauth-keys-generate](/docs/introduction/console-commands-for-application-management-phing-targets.md#backend-api-oauth-keys-generate) phing target to generate OAuth keys
+- read [Introduction to Backend API](/docs/backend-api/introduction-to-backend-api.md) to learn how to start using API in your project