add: project rank and user rank api

app/controllers/project_rank_controller.rb

@@ -0,0 +1,24 @@
+class ProjectRankController < ApplicationController
+  # 根据时间获取热门项目
+  def index 
+    $redis_cache.zunionstore("recent-days-project-rank", get_timeable_key_names)
+    @project_rank = $redis_cache.zrevrange("recent-days-project-rank", 0, 5, withscores: true)
+  rescue Exception => e
+    @project_rack = []
+  end
+
+  private 
+  # 默认显示7天的
+  def time
+    params.fetch(:time, 7).to_i
+  end
+
+  def get_timeable_key_names
+    names_array = []
+    (0...time).to_a.each do |i|
+      date_time_string = (Date.today - i.days).to_s
+      names_array << "v2-project-rank-#{date_time_string}"
+    end
+    names_array
+  end
+end