Added new examples of select and pairs queries.

[mRrvz]

Closes #49

[olegrok]

Hi! Thanks for your patch, consider several comments below.

[olegrok]

Thanks for your changes. Consider several comments below.

[dokshina]

Please, fix @olegrok comments and then feel free to merge.

Thanks a lot for these examples!

[Totktonada]

@mRrvz How bucket IDs are calculated? I can't get those values from permutations of given field values using require('vshard.hash').<..strcrc32 or mpcrc32..>({<...>}) % <...> + 1.

[mRrvz]

@Totktonada hi! To be honest, I don't remember anymore. I think we need to ask @olegrok or @dokshina.

[olegrok]

@mRrvz How bucket IDs are calculated? I can't get those values from permutations of given field values using require('vshard.hash').<..strcrc32 or mpcrc32..>({<...>}) % <...> + 1.

I think it's strcrc32 with bucket_count = 3000

[Totktonada]

@olegrok I tried strcrc32 and mpcrc32 with bucket_count = 10000 for the primary key and different permutations of other fields. bucket_count = 3000 is impossible, because we have bucket_id = 7331. If bucket_count is not 10000, but X*1000, I would anyway see the same last three digits.