Resolve "Borestop"

Closes #25 (closed)

borestop/src/main/java/com/ippon/borestop/activity/domain/Activities.java

+package com.ippon.borestop.activity.domain;
+
+public class Activities {
+  private final IdeasRepository ideas;
+  private final PartnersRepository partners;
+
+  public Activities(IdeasRepository ideas, PartnersRepository partners) {
+    this.ideas = ideas;
+    this.partners = partners;
+  }
+
+  public Activity next() {
+    Idea idea = ideas.next();
+
+    Partners matchingPartners = partners.find(idea.getCategory());
+
+    return new Activity(idea, matchingPartners);
+  }
+}