Collection name validation is too strict

[ghost]

Case

Bug

Issue

The regular expression here:

rxdb/src/util.js

Line 194 in 41cb52e

const regStr = '^[a-z][a-z0-9]*$';

The link here:

rxdb/src/util.js

Line 171 in 41cb52e

* @link https://wiki.apache.org/couchdb/HTTP_database_API

Is 404 Not Found, but an older version of it says:

A database must be named with all lowercase letters (a-z), digits (0-9), or any of the ''_$()+-/'' characters and must end with a slash in the URL. The name has to start with a lowercase letter (a-z).

This suggests that a more accurate regex would be ^[a-z][_$a-z0-9]*$ (excluding ()+-/ because they are not valid in JavaScript identifiers).

[ghost]

If you don't want to allow $ and _ in the terminal position because it's reserved, I can amend the regex in my PR for that.
I really just want an underscore in the middle of a name.

[pubkey]

Hi @errorx666 thank for the PRs and Issues. I am currently working hard on rxdb v8.0. The review will take a while but will come. Just that you know..