Add optional authored Ruins structures to Ages (#91)

build.gradle

@@ -245,6 +245,11 @@ dependencies {
     // Keep them on the compile classpath without forcing either mod at runtime.
     compileOnly "net.createmod.ponder:ponder-neoforge:${ponder_version}+mc${minecraft_version}"
     compileOnly "maven.modrinth:immersive-portals-neoforge:${immersive_portals_version}"
+    // Ruins is optional; its pre-spawn event is only registered when Ruins is loaded.
+    compileOnly 'curse.maven:ruins-227873:6391825'
+    if (providers.gradleProperty('withRuins').map { it.toBoolean() }.orElse(false).get()) {
+        localRuntime 'curse.maven:ruins-227873:6391825'
+    }
     // TerraBlender's region API is only used by the guarded compat adapter.
     compileOnly "com.github.glitchfiend:TerraBlender-neoforge:${minecraft_version}-${terrablender_version}"
     if (providers.gradleProperty('withTerraBlender').map { it.toBoolean() }.orElse(false).get()) {