Add custom prefixes

[TimurSultanov]

Added an ability to add custom prefixes to the validator.

[coveralls]

Pull Request Test Coverage Report for Build 46

• 14 of 14 (100.0%) changed or added relevant lines in 3 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 100.0%

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Totals
Change from base Build 42:	0.0%
Covered Lines:	248
Relevant Lines:	248

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💛 - Coveralls

[radarlog]

@TimurSultanov thank you for the contribution.

The GTIN specification has defined all possible prefixes in a very precise way.

What's the purpose of you PR?

[TimurSultanov]

@radarlog We should use some custom prefixes in our company, for example "250"
One vendor creates GtINs with this prefix, and we should handle this situation.
Perhaps in the future we will have more custom prefixes.

[radarlog]

According to the current implementation prefixes from the range 200-299 are used to issue Restricted Circulation Numbers within a company. According to the actual specification from above it still so (please check Figure 1.4.3-1)

[TimurSultanov]

I see, but we need these prefixes for internal using.

[radarlog]

Current implementation follows the GTIN specification as strict as possible.

Since you propose something very internal and specific to your business, I cannot accept your changes into the upstream.

I would rather suggest you to fork the library and adjust it according to your needs (as you already have actually done).

Hope for your understanding!

[TimurSultanov]

Thank you