You have a few options, here are two that I have used.
1: Download the TFS 2012 MSSCCI Provider:
This plugin allows you to access TFS from Microsoft SQL Server Management Studio. So you can easily add and check in\out those ssmssln and ssmsproj files from TFS.
64bit Download - 32bit Download
Once installed, in SSMS go to Tools-> Options -> Source Control to select the plugin.
If you don't see it then you probably need to install the other bit version.
After you have selected the plugin in the options window of SSMS, you will have a new menu option under "File" that will allow you to Add\Open\Change items in TFS from Sql Management Studio.
To add your Scripts solution using the MSSCCI plugin:
Open the project in SSMS, go to File -> Source Control -> Add Solution to Source Control
2. Add through VS using the "Add files to Source Control"
See here: To add a file that is not in a solution to version control