Add method to update (one or multiple rows) specifying the columns to be updated

[gustavotero7]

Summary

Some times we need to specify the column name(s) when updating a row, it's more useful than specifying the columns to be ignored when we have big models and want to update only a few fields.

Usage

...
    user.Email = "rick@example.com"
    if err := tx.UpdateColumns(&user, "email"); err != nil {
        log.Print(err)
    }
...

Tests

SODA_DIALECT=sqlite go test -cover -tags "sqlite" ./...
ok  	github.com/gobuffalo/pop	2.237s	coverage: 60.9% of statements
ok  	github.com/gobuffalo/pop/associations	(cached)	coverage: 47.6% of statements
ok  	github.com/gobuffalo/pop/columns	(cached)	coverage: 89.0% of statements
ok  	github.com/gobuffalo/pop/fix	(cached)	coverage: 93.5% of statements
ok  	github.com/gobuffalo/pop/genny/config	(cached)	coverage: 100.0% of statements
ok  	github.com/gobuffalo/pop/genny/fizz/cempty	(cached)	coverage: 82.1% of statements
ok  	github.com/gobuffalo/pop/genny/fizz/ctable	(cached)	coverage: 78.8% of statements
ok  	github.com/gobuffalo/pop/genny/model	0.971s	coverage: 90.1% of statements
ok  	github.com/gobuffalo/pop/internal/defaults	(cached)	coverage: 100.0% of statements
?   	github.com/gobuffalo/pop/internal/oncer	[no test files]
ok  	github.com/gobuffalo/pop/internal/randx	(cached)	coverage: 100.0% of statements
?   	github.com/gobuffalo/pop/logging	[no test files]
ok  	github.com/gobuffalo/pop/nulls	(cached)	coverage: 0.0% of statements
?   	github.com/gobuffalo/pop/packrd	[no test files]
ok  	github.com/gobuffalo/pop/slices	(cached)	coverage: 29.4% of statements
?   	github.com/gobuffalo/pop/soda	[no test files]
ok  	github.com/gobuffalo/pop/soda/cmd	(cached)	coverage: 23.3% of statements
ok  	github.com/gobuffalo/pop/soda/cmd/generate	1.201s	coverage: 33.1% of statements
?   	github.com/gobuffalo/pop/soda/cmd/schema	[no test files]

[mclark4386]

Looks great! Would you mind improving the test coverage on it a bit (mainly thinking about giving more than one column name to update)?

[gustavotero7]

Looks great! Would you mind improving the test coverage on it a bit (mainly thinking about giving more than one column name to update)?

Hi, @mclark4386 Thanks 😃
I have added a couple of tests to cover more scenarios, let me know WDYT.

[gustavotero7]

Hi guys, any update on this? @mclark4386 @stanislas-m

[mclark4386]

Looks good! Thanks for the tweaks and fuller testing!