added servant-0.4 template

[soenkehahn]

This PR adds a slightly bigger template for servant-0.4.

I put it in a subdirectory, because I thought it would make sense to start to organize the templates a bit, but I don't know if this'll actually work with stack new. I can move it to the root dir, of course.

[mgsloan]

I don't think this works, because of things like stack templates, which lists the templates by enumerating the dir on github. The easiest way to lift that restriction would probably be to implement commercialhaskell/stack#1595

It would make sense to organize templates a little more. With autocompletion, this could work rather well. So you type "web/" + TAB and find out all the web templates.

[prikhi]

Related: I've created a servant-postgresql template for servant 0.5 & was wondering about a couple things:

• Would this be accepted? Are there some sort of minimum requirements for new templates or will you accept anything useful & working? Is there a limit to how indepth a template can be(maybe that's more an on individual basis)?
• Is there a way to compose templates? So this template & my template could reuse the Test file instead of having to duplicate the code?
• Is there some sort of style guide for the final app? For instance, when specifying the executable, should Main.hs live in app/ or bin/ or exe/ or something else?
• Is there a way to get stack to add servant-0.5 & servant-server-0.5 to the extra-deps in stack.yml when generating the app? Or should I rely on the cabal file & expect people to add --solver to their stack new command?

I will make a separate PR when I have some extra time.

[soenkehahn]

@mgsloan: I've put the file in the root directory. I've also renamed it to indicate that it uses hspec-wai-json.

@prikhi: See a related discussion here: https://groups.google.com/d/topic/haskell-stack/sOI5rY28G3E/discussion

[mgsloan]

@prikhi Not really the best place to discuss, I have opened a few issues:

#55
commercialhaskell/stack#1994
#56

[mgsloan]

I'd really prefer a short name. Imagine someone typing this in! We do not have shell autocompletion of template names yet. servant or servant-0.4 is fine.

I'm actually on the wall as to whether it's useful to have templates for specific libraries like this, as described in #55 . I really don't want to start seeing lens-aeson-hspec-containers templates.

In the meantime I'm happy to merge very library specific templates, but the policy may change. I don't really want the default library creation process to include "make a stack template"

[soenkehahn]

@mgsloan: That makes a lot of sense. I've renamed it to servant-0.4. (There's already a servant template.)

[mgsloan]

Oops forgot to merge. Thanks!