Update Issue type about issue-wanted

[chshersh]

@rashadg1030 We don't need FromJSON instance. Regarding the problem with ToJSON instance: you can store a plain list of values inside the Issue data type and wrap it in PGArray only in the ToRow/FromRow instances. This means that you cannot derive those instances automatically, you need to write them manually. But what can be done... You either need to write manual JSON or Row instances. And let's not have orphan instances. Manual wrapping and unwrapping is better for the maintainability.

[rashadg1030]

Is there a ToRow/FromRow instance for type [a], or do I have to roll my own? The Issue type has a labels :: [Text] field. How do we get this to an SQL array?

[rashadg1030]

https://www.stackage.org/haddock/nightly-2019-06-27/postgresql-simple-0.6.2/Database-PostgreSQL-Simple-Types.html
I think I found something newtype PGArray a

[chshersh]

@rashadg1030 Yes, for arrays you need to use PGArray newtype

[rashadg1030]

@chshersh Okay so Issue now has a PGArray Text field. I have a ToJSON instance for Issue. I'm trying to roll the FromJSON instance, but I was thinking if we even need an instance because we're using the github api. Maybe we still need it for something else though

[rashadg1030]

instance (ToJSON a) => ToJSON (PGArray a) where
  toJSON :: PGArray a -> Value 
  toJSON = toJSON . fromPGArray

I get an orphan instance warning. It's telling me to either:

 move the instance declaration to the module of the class or of the type, or
 wrap the type with a newtype and declare the instance on the new type.