#115 - Mapping - Add support for @ElementCollection enhancement

Initial support - simple List.

src/main/java/io/ebeaninternal/server/query/ExtraJoin.java

@@ -0,0 +1,20 @@
+package io.ebeaninternal.server.query;
+
+public class ExtraJoin {
+
+  private final STreePropertyAssoc property;
+  private final boolean containsMany;
+
+  public ExtraJoin(STreePropertyAssoc property, boolean containsMany) {
+    this.property = property;
+    this.containsMany = containsMany;
+  }
+
+  public STreePropertyAssoc getProperty() {
+    return property;
+  }
+
+  public boolean isContainsMany() {
+    return containsMany;
+  }
+}