My company uses a combination of some database tables, a web page front end and an \"export\" application to handle our string resources in our web sites.
The export
If you prefer to automatically generate the *.designer.cs files from *.resx files when building the project, the following approach worked for us and it might work for you as well:
This solution is based on all resource files being listed as "EmbeddedResource" within an ItemGroup of the project file, e.g.
PublicResXFileCodeGenerator Display_Creditor.Designer.cs Acme.Web.Resources.Creditor PublicResXFileCodeGenerator Tooltip_InboundEmailDetails.Designer.cs Acme.Web.Resources.InboundEmail PublicResXFileCodeGenerator Tooltip_CreditorDetails.Designer.cs Acme.Web.Resources.Creditor
Disclaimer: This has been tested with Visual Studio 2013 and C# projects. It may or may not work for other projects and/or other versions of Visual Studio.