Add pg as a peer dependency

[MichielDeMey]

Might be better suited for this package to add pg as a peer dependency to allow developers to use their preferred version of pg and to avoid mixing pg versions.

Any specific thoughts on this?

[cemremengu]

I think that should be fine, would you like to send a PR?

[MichielDeMey]

I'll have a PR up shortly. 👍

[MichielDeMey]

Should we follow @mcollina's example and add pg as a devDependency?
(cfr. https://github.com/brianc/node-pg-pool/blob/master/package.json#L34)

or

Keep it as a main dependency, which means that this library will dictate the pg version to be used.

In case of option 1, adding it as a devDependency here as well as a peerDependency forces developers to specify the pq library and version in their main project which could prevent incompatibility issues that would arise from this library dictating the version.

So installation will be npm install pg fastify-postgres

Option 1 is not backwards compatible, NPM 3+ will complain in case pg is not installed in the main project. So we'll have to bump the major version of this library.
Option 2 is backward compatible, but then this library would dictate the pg version with possible incompatibility issues later on.

What's your opinion? (Maybe @mcollina could chime in as well?)

[mcollina]

I'm +1 with option 1.

[cemremengu]

I think adding it as a devDependency + a peerDependency is better but decision is up to @mcollina

[mcollina]

+1 with option 1.