11. follow user : the beginning
11. follow user : the beginning 2
Merge branch 'master' into following-user
11.1.2 is over:  association with relationship model
11.1.2 is over:  association with relationship model
11.1.3~5 is over:  relationship model validates, follow user, unfolow user
11.2.1~2 is over:

11.2.1. follow user 's sample data
11.2.2. following statics
            follow and unfollow form (button)
source review modify

魚さんへ：
コメントアウトの内容には、勉強のため（再参考）に、
残しています。
11.2.3 is over:

* main:
to show following users list and follower users list

* others:
1. to move the per_page setting into model
2. make the empty relationship controller (WIP)
11.2.4 is over: normal way to follow and unfollow user
Merge pull request #7 from cooltiger/following-user

Following user