Merge pull request #1948 from Gallimathias/update/readme_april

Update/readme april

.gitignore

@@ -1,2 +1,5 @@
 # Binary files
-*.app
+*.app
+
+# Temp files
+.vs/

README.MD

@@ -1,7 +1,7 @@
 
 # AL Development for Dynamics 365 Business Central
  <!-- [![Released version](https://img.shields.io/badge/Release_version-0.12.15355-green.svg?style=flat-square)](https://mbs.microsoft.com/partnersource/global/deployment/downloads/product-releases/msdnav2018download) -->
- [![current preview version 0.14.17461](https://img.shields.io/badge/Current_Preview_Version-0.14.17461-orange.svg?style=flat-square)](https://github.com/Microsoft/AL/milestone/14) [![next preview update March 2018](https://img.shields.io/badge/Next_Preview_Update-March_2018-blue.svg?style=flat-square)](https://github.com/Microsoft/AL/milestone/15)
+ [![current preview version 0.15.18771](https://img.shields.io/badge/Current_Preview_Version-0.15.18771-orange.svg?style=flat-square)](https://github.com/Microsoft/AL/milestone/15) [![next preview update May 2018](https://img.shields.io/badge/Next_Preview_Update-May_2018-blue.svg?style=flat-square)](https://github.com/Microsoft/AL/milestone/16)
 
 ---
 
@@ -17,7 +17,7 @@ For documentation about extending Dynamics 365 Business Central, get started wit
 •	[Developer Reference](https://docs.microsoft.com/en-us/dynamics-nav/)  
 
 ## Get the AL developer experience
-To develop and deploy code created in AL, you must have the latest [Developer Preview](https://aka.ms/navdeveloperpreview).
+To develop and deploy code created in AL, you must have the latest [Developer Preview](http://aka.ms/bcsandbox).
 
 ## FAQ
 Our answers to frequently asked questions can be found in our [Wiki](https://github.com/Microsoft/AL/wiki/Frequently-Asked-Questions).