Build fails with Go 1.13.4

[atombender]

$ go version
go version go1.13.4 darwin/amd64
$ mkdir go
$ export GOPATH=$PWD/go
$ go get -u github.com/amacneil/dbmate
# github.com/amacneil/dbmate
go/src/github.com/amacneil/dbmate/main.go:33:17: cannot use cli.StringFlag literal (type cli.StringFlag) as type cli.Flag in array or slice literal:
	cli.StringFlag does not implement cli.Flag (Apply method has pointer receiver)
go/src/github.com/amacneil/dbmate/main.go:38:17: cannot use cli.StringFlag literal (type cli.StringFlag) as type cli.Flag in array or slice literal:
	cli.StringFlag does not implement cli.Flag (Apply method has pointer receiver)
go/src/github.com/amacneil/dbmate/main.go:43:17: cannot use cli.StringFlag literal (type cli.StringFlag) as type cli.Flag in array or slice literal:
	cli.StringFlag does not implement cli.Flag (Apply method has pointer receiver)
go/src/github.com/amacneil/dbmate/main.go:48:15: cannot use cli.BoolFlag literal (type cli.BoolFlag) as type cli.Flag in array or slice literal:
	cli.BoolFlag does not implement cli.Flag (Apply method has pointer receiver)
go/src/github.com/amacneil/dbmate/main.go:54:15: cannot use []cli.Command literal (type []cli.Command) as type []*cli.Command in assignment
go/src/github.com/amacneil/dbmate/main.go:138:25: c.GlobalBool undefined (type *cli.Context has no field or method GlobalBool)
go/src/github.com/amacneil/dbmate/main.go:139:23: c.GlobalString undefined (type *cli.Context has no field or method GlobalString)
go/src/github.com/amacneil/dbmate/main.go:140:20: c.GlobalString undefined (type *cli.Context has no field or method GlobalString)
go/src/github.com/amacneil/dbmate/main.go:148:10: c.GlobalString undefined (type *cli.Context has no field or method GlobalString)

[gonzigonz]

use GO111MODULE=on go get -u github.com/amacneil/dbmate

This is now required as https://github.com/urfave/cli recently changed their api in v2 and without any form of vendoring people would experience this issue. urfave/cli#925

So there are two options (same as discussed in that issue):

1. change your code to use go modules so you can pin v1, or
2. update the flag interface for the v2 api changes

dbmate does use go modules to build but installing directly like you are you'll have have to vendor yourself. Option two can easily be done but at the time urfave/cli v2 was still in alpha although I think that has changed now. So the example above is your option 1 solution.

If there is any appetite for an update to use v2 and match the API change I'd be happy to PR

[atombender]

Thanks. You may want to put this in the readme.

[gonzigonz]

@amacneil let us know if a PR for either of the commits referenced above interest you.

[amacneil]

Both commits look good, happy to accept PRs! Thanks