Move gql handler out of main, improve admin route matching

pkg/api/http.go

@@ -0,0 +1,21 @@
+package api
+
+import (
+	"net/http"
+
+	"github.com/99designs/gqlgen/graphql/handler"
+	"github.com/99designs/gqlgen/graphql/playground"
+	"github.com/gorilla/mux"
+)
+
+func HTTPHandler(resolver *Resolver, gqlEndpoint string) http.Handler {
+	router := mux.NewRouter().SkipClean(true)
+	router.Methods("POST").Handler(
+		handler.NewDefaultServer(NewExecutableSchema(Config{
+			Resolvers: resolver,
+		})),
+	)
+	router.Methods("GET").Handler(playground.Handler("GraphQL Playground", gqlEndpoint))
+
+	return router
+}