Replace UNION ALL query string with DSL

[Libbum]

oration/src/models/comments/mod.rs

Lines 374 to 380 in 41d7f01

	//NOTE: UNION ALL and WITH RECURSIVE are currently not supported by diesel
	//https://github.com/diesel-rs/diesel/issues/33
	//https://github.com/diesel-rs/diesel/issues/356
	//So this is implemented in native SQL for the moment
	//TODO: since SqlLiteral#bind is depreciated, we should be using `sql_query`
	//here. However: we're building a virtual table and pulling a count from it.
	//Diesel for the moment AFAIK is not a happy camper about this.

This issue has a fix now (I think), so we can take a look at re-implementing this method.