Ensure all new classes have reasonable groovydoc/javadoc (#364)

Author: ysb33r

core-plugin/src/main/groovy/com/github/jrubygradle/core/ApiException.groovy

@@ -5,6 +5,7 @@ import groovy.transform.InheritConstructors
 
 /** Throws when there are issues with the RubyGems REST API.
  *
+ * @since 2.0
  */
 @InheritConstructors
 @CompileStatic

core-plugin/src/main/groovy/com/github/jrubygradle/core/GemDependency.java

@@ -1,7 +1,20 @@
 package com.github.jrubygradle.core;
 
+/** Description of a transitive GEM dependency.
+ *
+ * @since 2.0
+ */
 public interface GemDependency {
+
+    /** Name of transitive GEM dependency.
+     *
+     * @return GEM name
+     */
     String getName();
 
+    /** Version requirements that is requested upon this transitive dependency.
+     *
+      * @return Version requirements in GEM format.
+     */
     String getRequirements();
 }

core-plugin/src/main/groovy/com/github/jrubygradle/core/GemInfo.java

@@ -3,6 +3,10 @@
 import java.net.URI;
 import java.util.List;
 
+/** GEM metadata.
+ *
+ * @since 2.0
+ */
 public interface GemInfo {
 
     /** GEM name.