Add optional authored Ruins structures to Ages (#91)

src/main/resources/assets/rivencraft/lang/en_us.json

@@ -431,6 +431,8 @@
   "rivencraft.ponder.crystal_portal.text_3": "Insert a bound Linking or Descriptive Book to activate the portal.",
   "rivencraft.ponder.crystal_portal.text_4": "Step through the portal. Remove the book to close it.",
   "itemGroup.rivencraft": "Rivencraft",
+  "itemGroup.rivencraft.pages.ruins": "Rivencraft Ruins Pages",
+  "symbol.rivencraft.ruins.description": "Allows this Ruins template to appear in the Age.",
   "itemGroup.rivencraft.pages.link": "Rivencraft Link Pages",
   "itemGroup.rivencraft.pages.terrain": "Rivencraft Terrain Pages",
   "itemGroup.rivencraft.pages.biome": "Rivencraft Biome Pages",

src/main/resources/rivencraft.mixins.json

@@ -9,6 +9,9 @@
     "AgeDungeonPlacementMixin",
     "AgeStructureBiomeMixin",
     "MobDropChanceAccessor",
+    "RuinsDimensionMixin",
+    "RuinsAttemptMixin",
+    "RuinsTemplateDimensionMixin",
     "StructurePlacementAccessor"
   ],
   "client": [