chore: show on ReadPlan and MediaType

src/PostgREST/SchemaCache/Relationship.hs

@@ -34,7 +34,7 @@ data Relationship = Relationship
   , relToOne        :: Bool
   , relIsSelf       :: Bool
   }
-  deriving (Eq, Ord, Generic, JSON.ToJSON)
+  deriving (Eq, Show, Ord, Generic, JSON.ToJSON)
 
 -- | The relationship cardinality
 -- | https://en.wikipedia.org/wiki/Cardinality_(data_modeling)
@@ -47,7 +47,7 @@ data Cardinality
   -- ^ one-to-one, this is a refinement over M2O so operating on it is pretty much the same as M2O
   | M2M Junction
   -- ^ many-to-many
-  deriving (Eq, Ord, Generic, JSON.ToJSON)
+  deriving (Eq, Show, Ord, Generic, JSON.ToJSON)
 
 type FKConstraint = Text
 
@@ -59,7 +59,7 @@ data Junction = Junction
   , junColsSource  :: [(FieldName, FieldName)]
   , junColsTarget  :: [(FieldName, FieldName)]
   }
-  deriving (Eq, Ord, Generic, JSON.ToJSON)
+  deriving (Eq, Show, Ord, Generic, JSON.ToJSON)
 
 -- | Key based on the source table and the foreign table schema
 type RelationshipsMap = HM.HashMap (QualifiedIdentifier, Schema)  [Relationship]