* Rail Fence Cipher completed

* Added @Ignore in the test file

* Build fail corrections

* Build Fail

* Added .keep file, the abscence caused build to fail

* Changes done as per the recent conventions

* Modified the config.json adding topics as well

* Update config.json

* rail-fence-encoding: add to config.json

* rail-fence-cipher: improve reference solution

* rail-fence-cipher: update with @FridaTveit's suggestions.