How to move SSAS tabular instance databases?
You can back up and restore SSAS Tabular 2012 databases, but you will have to adjust the security role memberships to include users in the correct domain. You can perform the backup and restore manually or through a script in Management Studio (or executed via PowerShell).  

You can also re-deploy an SSAS database from the SSDT project or using the SSAS Deployment wizard. The wizard will allow you to deploy roles and ignore members. Next populate the role memberships with appropriate users. From there, you can process the model to populate it and bring the model online.  

Another option is to script the SSAS database from Management Studio. Once you do this you can remove the  collection from each role and execute the XMLA on your target server.