Update initialize-database.rst (#11109)
Update initialize-database.rst (#11109)

* Update initialize-database.rst

Remove ambiguity in the language as only MySQL, Postgres and SQLite are supported backends.

* Update docs/howto/initialize-database.rst

Co-authored-by: Jarek Potiuk <0b79f5e5f0bba1537eabb84336faddabf8b19142@potiuk.com>

Co-authored-by: Xiaodong DENG <88c52341fa08274ad1da50d9b97f03e6c2a64b73@gmail.com>
Co-authored-by: Jarek Potiuk <0b79f5e5f0bba1537eabb84336faddabf8b19142@potiuk.com>
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