Document authentication

[miohtama]

How to pass the password to the PSQL connection is not obvious from the current documentation.
Add a basic example with links to the more documentation.

[dlax]

@miohtama, thank you for your contribution!

@blogh, what do you think about this addition?

[dlax]

It's not specific to psycopg2, it's just libpq:

Suggested change

	supported by `psycopg2` library.
	supported by `libpq`.

[blogh]

This is a libpq feature and there are many different ways to do this.

I'd rather have this in the FAQ part and would prefer something like :

pg_activity uses libpq to access to PostgreSQL. All the traditional methods are available.

You can pass the password for the database connection in a password file. Information can also be given
via PostgreSQL's environment variables (PGPASSFILE or PGPASSWORD) or via the connection string parameters.

The password file is preferred since it's more secure (security is deferred to the OS). Please avoid password in connection strings at all cost.

[blogh]

Also : @miohtama, thank you for your contribution :)

[blogh]

Are you guys ok with this ? If so I can do the PR.

[dlax]

Are you guys ok with this ? If so I can do the PR.

Yes.

[blogh]

Pushed it that way.

@miohtama, thanks for the patch
@dlax, thanks for reviewing