Update 'README.md'

2019-05-16 07:49:06 +00:00 · 2019-05-16 07:49:06 +00:00 · 2d7a117197
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 # See [`greenlock-store-test`](https://git.rootprojects.org/root/greenlock-store-test.js)
+
+That's the test.
+
+## Reference implementations
+
+* [`greenlock-store-fs`](https://git.rootprojects.org/root/greenlock-store-fs.js)
+* [`greenlock-store-sequelize`](https://git.rootprojects.org/root/greenlock-store-sequelize.js)