Allow specifying tag in toml config file

[peterrus]

It looks like it is currently not possible to specify a tag in the config file. I think it'd be useful if the config file format supports the equivalent of the command line interface's --tag.

[dufferzafar]

@zyedidia we do have a tag param in the ConfigRepository -

eget/config.go

Line 38 in 0983dea

Tag string `toml:"tag"`

does this not already work?

[cj81499]

@dufferzafar Even if it already works (Which it very well may! I haven't tried recently), it's undocumented in the Configuration section of the README.