add migration guide

Author: liborm85

content/document-definition-object/page.md

@@ -71,8 +71,12 @@ var dd = {
        {text: '3 Headline', headlineLevel: 1},
        'Some long text of variable length ...',
     ],
-  pageBreakBefore: function(currentNode, followingNodesOnPage, nodesOnNextPage, previousNodesOnPage) {
-     return currentNode.headlineLevel === 1 && followingNodesOnPage.length === 0;
+  pageBreakBefore: function(currentNode, nodeContainer) {
+    // nodeContainer.getFollowingNodesOnPage();
+    // nodeContainer.getNodesOnNextPage();
+    // nodeContainer.getPreviousNodesOnPage();
+
+    return currentNode.headlineLevel === 1 && nodeContainer.getFollowingNodesOnPage().length === 0;
   }
 }
 ```

content/migration-from-0.1/_index.md

@@ -0,0 +1,38 @@
++++
+title = "Migration from 0.1"
+description = ""
+weight = 9
+alwaysopen = true
++++
+
+#### Unified interfaces and all methods return promise
+
+[See Methods for client-side](/docs/0.3/getting-started/client-side/methods/).
+
+[See Methods for server-side](/docs/0.3/getting-started/server-side/methods/).
+
+
+#### Changed including virtual font storage in client-side
+
+Regenerate virtual file system (VFS) is required.
+
+
+#### Changed parameters of pageBreakBefore function
+
+Version 0.1 or 0.2:
+```js
+  pageBreakBefore: function(currentNode, followingNodesOnPage, nodesOnNextPage, previousNodesOnPage) {
+
+  }
+```
+
+Version 0.3:
+```js
+  pageBreakBefore: function(currentNode, nodeContainer) {
+    // nodeContainer.getFollowingNodesOnPage();
+    // nodeContainer.getNodesOnNextPage();
+    // nodeContainer.getPreviousNodesOnPage();
+  }
+```
+
+[See documentation](/docs/0.3/document-definition-object/page/#dynamically-control-page-breaks-for-instance-to-avoid-orphan-children).