Add flask sample

[kouul]

No description provided.

[glours]

Hello @kouul,

Thanks for your PR!
We already have 2 samples with flask, one with nginx and mongo and an another one with nginx and mysql
Maybe we just need to improve the existing ones if needed, what do you think?

[kouul]

Hi @glours

Yes, but there is no sample of a plain flask application. By plain I mean without any connection to any db. It could be easier for someone to use this one to connect to another db other than Mysql or mongo.

[aiordache]

Thank you @kouul
It sounds good to me to have more single service samples, we added some already. If I would like to run a simple python service, this may be useful as I wouldn't need to cleanup the other samples just to get my flask one.

[glours]

Can you add your sample in the main README.md, please?

[glours]

Thank you very much for your contribution @kouul 🙏