[Proposal] Add model token limits to tiktoken_ruby

[mattlindsey]

Would you be opposed to adding token limits to https://github.com/IAPark/tiktoken_ruby/blob/main/lib/tiktoken_ruby.rb and a get_token_limit method?
Seems better here than in the project I'm helping with (https://github.com/andreibondarev/langchainrb).

TOKEN_LIMITS = {
# Source:
# https://platform.openai.com/docs/api-reference/embeddings
# https://platform.openai.com/docs/models/gpt-4
"text-embedding-ada-002" => 8191,
"gpt-3.5-turbo" => 4096,
"gpt-3.5-turbo-0301" => 4096,
"text-davinci-003" => 4097,
"text-davinci-002" => 4097,
"code-davinci-002" => 8001,
"gpt-4" => 8192,
"gpt-4-0314" => 8192,
"gpt-4-32k" => 32768,
"gpt-4-32k-0314" => 32768,
"text-curie-001" => 2049,
"text-babbage-001" => 2049,
"text-ada-001" => 2049,
"davinci" => 2049,
"curie" => 2049,
"babbage" => 2049,
"ada" => 2049
}

[IAPark]

Ah, do you know if that's part of the python tiktoken library?