Fixes groovydoc task: because no Groovy Jar was found on class path

Closes gh-78

Author: rainboyan

build.gradle

@@ -17,10 +17,19 @@ ext.isReleaseVersion = !projectVersion.endsWith("SNAPSHOT")
 version = project.projectVersion
 group = "org.graceframework"
 
+repositories {
+    mavenCentral()
+}
+
 configurations {
     documentation
 }
 
+dependencies {
+    documentation libs.javaparser
+    documentation libs.groovy.core
+}
+
 def cleanTask = project.tasks.findByName('clean')
 if (cleanTask == null) {
     task clean(type: Delete) {