Add Migrations to docs header (#386)

* Docs: add Migrations to header

* fix diff

docs/docs/20-usage/30-matrix-builds.md

@@ -60,8 +60,8 @@ Example Yaml file after injecting the matrix parameters:
 ```diff
 pipeline:
   build:
--   image: golang:${GO_VERSION}
-+   image: golang:1.4
+-   image: golang:1.4
++   image: golang:${GO_VERSION}
     commands:
       - go get
       - go build
@@ -72,8 +72,8 @@ pipeline:
 
 services:
   database:
--   image: ${DATABASE}
-+   image: mysql:5.5
+-   image: mysql:5.5
++   image: ${DATABASE}
 ```
 
 ## Examples

docs/docusaurus.config.js

@@ -34,6 +34,12 @@ module.exports = {
           position: 'left',
           label: 'FAQ',
         },
+        {
+          type: 'doc',
+          docId: 'migrations',
+          position: 'left',
+          label: 'Migrations',
+        },
         // {to: '/blog', label: 'Blog', position: 'left'},
         {
           href: 'https://github.com/woodpecker-ci/woodpecker',