Add related work

[koppor]

I like if tools and libraries provides comparison of themselves to others. Common in the LaTeX world :p (And I maintain the Markdown Any Decision Records which focus on the options for a decision, in contrast to Nygard'S ADRs)).

We should add a comparison to https://github.com/microsoft/credential-secure-storage-for-java

First impression: They do not support KDE, the API might be less well-designed than the one of java-keyring.

[rexhoffman]

Lack of CI config and tests verifying it works also stand out.