Add jumpingcastle as a gradle dependency

build.gradle

@@ -49,6 +49,7 @@ targetCompatibility = 1.8
 
 sourceSets {
     external {
+				compileClasspath += main.compileClasspath
     }
     main {
         compileClasspath += external.output
@@ -56,6 +57,15 @@ sourceSets {
     }
 }
 
+repositories {
+    flatDir {
+        dir 'lib'
+    }
+}
+dependencies {
+    deobfCompile('com.minelittlepony:jumpingcastle:1.12.2.1.0.0:universal')
+}
+
 jar {
 		def props = [
 				modid: project.modid,