Adding docs into core repo again

docs/upgrading.md

@@ -0,0 +1,28 @@
+# Upgrading
+
+Some of the interfaces has been upgraded.
+
+
+## From version 0.4.0 to 0.5.0
+
+
+### Initialization
+
+`mermaid_config` is no longer used. Instead a call to mermaid initialize is done as in the example below:
+
+
+#### version 0.4.0
+
+```javascript
+mermaid_config = {
+    startOnLoad: true
+}
+```
+
+#### version 0.5.0
+
+```javascript
+mermaid.initialize({
+    startOnLoad: true
+})
+```