Support MySQL

[leafo]

Add MySQL as a backend for the models and query helpers.

• lapis.db.mysql query functions
• lapis.db.mysql.schema schema functions
• lua-resty-mysql backend for server
• support for models
• query parser for pagination
• documentation
• integration specs that hit server

[josefnpat]

I feel getting MySQL more cleanly integrated would be a big boost for this project.

While many folks may consider postgresql to be superior, many folks just either a) use what they know, or b) use what they have.

On top of that, it should be rather easy to make MariaDB a simple drop on replacement for MySQL.

[dubcanada]

👍

[justicel]

Just wanted to add a 👍 to this as well. A feature I need pretty heavily to do any great amount of work with Lapis! Thanks for a great framework!

[neoascetic]

#158