Add exclude file configuration instructions and examples

Exclude-file-configuration.md

@@ -0,0 +1,32 @@
+As of commit 0714cbf basic exclude file from scan feature is supported in the dev build.
+
+Given a valid [regex](https://github.com/google/re2/wiki/Syntax), files that match even partially are excluded during the Scan process and are not entered in the database.
+Prior to matching both the filenames and patterns are converted to lower case so the match is case insensitive.
+
+Regex patterns can be added in the config file or from the UI.
+If you add manually to the config file a restart is needed while from the UI you just need to click the Save button.
+When added through the config file directly special care must be given to double escape the `\` character.
+
+Some examples
+
+For the config file you need the following added
+```
+exclude: 
+- "sample\\.mp4$"
+- "/\\.[[:word:]]+/"
+- "c:\\\\stash\\\\videos\\\\exclude"
+- "^/stash/videos/exclude/"
+- "^\\\\\\\\stash\\network\\\\share\\\\excl\\\\"
+```
+* the first excludes all files ending in `sample.mp4` ( `.` needs to be escaped also)
+* the second hidden directories `/.directoryname/`
+* the third is an example for a windows directory `c:\stash\videos\exclude`
+* the fourth the directory `/stash/videos/exclude/`
+* and the last a windows network path `\\stash\network\share\excl\`
+
+and thats how it looks if you use UI (notice the difference for the `\` character)
+
+![regexUI](https://i.imgur.com/3Oqvuja.png)
+
+_a useful [link](https://regex101.com/) to experiment with regexps_
+