Adding troubleshooting information about Subresource Integrity digests.

[dfbaskin]

Adding this section to the troubleshooting documentation:

Subresource integrity checks fail

Subresource Integrity digests are added to the build output files. For a particular scenario, these checks may fail when deployed. The files are built using LF characters, but if your deployment uses a Git repository for deployment (like Azure web sites) and the Git repository is set up to translate LF characters into CR/LF characters, then the checked out files will be different and the digests will be invalid.

To fix this, just add a .gitattributes file to your deployment repository that will ensure the build files are not modified when checked out:

*.css text eol=lf
*.js text eol=lf

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[gaearon]

Can we generate this file by default? Like we generate .gitignore.

[dfbaskin]

The .gitattributes file is for the deployment repository. Most folks using Git to deploy like this would create a separate repository for the output build files.

[gaearon]

Sounds good, thanks!