rails+AngularJSでAPIを利用して投稿に複数のタグを同時につけることやろうとしていますが、
うまくいきません。アドバイスいただけないでしょうか。

<やりたいこと>
ポストに対して1回のAPIで複数のタグレコードを検索、作成する。

＜POSTするJsonイメージ＞

[{name: 'tag1'},{name: 'tag2'}]

＜APIの処理＞

#ポストに紐づくタグの更新
resource "posts/:id/tag" do
  desc "投稿に紐づくタグ作成"
  params do
    requires :id, type: Integer, desc: "Post id."
  end
  post do
    @post = Post.find(params[:id])
    params[:name].each do |name|
      @post.tags.find_or_create_by({name: name)
    end
  end
end

上記の処理で下記のようなNoMethodErrorのエラーがでてしまいます。
そちら酒精したのですが、治らず。。。
下記のようなエラーが出ています。

NoMethodError at /api/v1/posts/1/tag
==================================== > undefined method `each' for "tag1":String app/api/aplication/api.rb, line 103
-------------------------------
``` ruby 
   98 params do 
   99   requires :id, type: Integer, desc: "Post id." 
  100 end 
  101 post do 
  102   @post = Post.find(params[:id])
> 103   params[:name].each do |name| 
  104     @post.tags.find_or_create_by({ 
  105       name: name 
  106     }) 
  107   end 
  108 end
``` App backtrace -------------

app/api/cospic/api.rb:103:in `block (2 levels) in ' Full backtrace --------------
app/api/cospic/api.rb:103:in `block (2 levels) in '
grape (0.10.1) lib/grape/endpoint.rb:47:in `block in generate_api_method'
grape (0.10.1) lib/grape/endpoint.rb:247:in `run'
grape (0.10.1) lib/grape/endpoint.rb:195:in `block in call!'
grape (0.10.1) lib/grape/middleware/base.rb:24:in `call!'
grape (0.10.1) lib/grape/middleware/base.rb:18:in `call'
grape (0.10.1) lib/grape/middleware/base.rb:24:in `call!'
grape (0.10.1) lib/grape/middleware/base.rb:18:in `call'
grape (0.10.1) lib/grape/middleware/error.rb:27:in `block in call!'
grape (0.10.1) lib/grape/middleware/error.rb:26:in `call!'
grape (0.10.1) lib/grape/middleware/base.rb:18:in `call'
rack (1.5.2) lib/rack/head.rb:11:in `call'
rack (1.5.2) lib/rack/builder.rb:138:in `call'
grape (0.10.1) lib/grape/endpoint.rb:196:in `call!'
grape (0.10.1) lib/grape/endpoint.rb:184:in `call'
rack-mount (0.8.3) lib/rack/mount/route_set.rb:152:in `block in call'
rack-mount (0.8.3) lib/rack/mount/code_generation.rb:96:in `block in recognize'
rack-mount (0.8.3) lib/rack/mount/code_generation.rb:68:in `optimized_each'
rack-mount (0.8.3) lib/rack/mount/code_generation.rb:95:in `recognize'
rack-mount (0.8.3) lib/rack/mount/route_set.rb:141:in `call'
grape (0.10.1) lib/grape/api.rb:102:in `call'
grape (0.10.1) lib/grape/api.rb:33:in `call!'
grape (0.10.1) lib/grape/api.rb:29:in `call'
actionpack (4.1.6) lib/action_dispatch/journey/router.rb:73:in `block in call'
actionpack (4.1.6) lib/action_dispatch/journey/router.rb:59:in `call'
actionpack (4.1.6) lib/action_dispatch/routing/route_set.rb:678:in `call'
omniauth (1.2.2) lib/omniauth/strategy.rb:186:in `call!'
omniauth (1.2.2) lib/omniauth/strategy.rb:164:in `call'
omniauth (1.2.2) lib/omniauth/builder.rb:59:in `call'
rack (1.5.2) lib/rack/config.rb:17:in `call'
warden (1.2.3) lib/warden/manager.rb:35:in `block in call'
warden (1.2.3) lib/warden/manager.rb:34:in `call'
rack (1.5.2) lib/rack/etag.rb:23:in `call'
rack (1.5.2) lib/rack/conditionalget.rb:35:in `call'
rack (1.5.2) lib/rack/head.rb:11:in `call'
actionpack (4.1.6) lib/action_dispatch/middleware/params_parser.rb:27:in `call'
actionpack (4.1.6) lib/action_dispatch/middleware/flash.rb:254:in `call'
rack (1.5.2) lib/rack/session/abstract/id.rb:225:in `context'
rack (1.5.2) lib/rack/session/abstract/id.rb:220:in `call'
actionpack (4.1.6) lib/action_dispatch/middleware/cookies.rb:560:in `call'
activerecord (4.1.6) lib/active_record/query_cache.rb:36:in `call'
activerecord (4.1.6) lib/active_record/connection_adapters/abstract/connection_pool.rb:621:in `call'
activerecord (4.1.6) lib/active_record/migration.rb:380:in `call'
actionpack (4.1.6) lib/action_dispatch/middleware/callbacks.rb:29:in `block in call'
activesupport (4.1.6) lib/active_support/callbacks.rb:82:in `run_callbacks'
actionpack (4.1.6) lib/action_dispatch/middleware/callbacks.rb:27:in `call'
actionpack (4.1.6) lib/action_dispatch/middleware/reloader.rb:73:in `call'
actionpack (4.1.6) lib/action_dispatch/middleware/remote_ip.rb:76:in `call'
better_errors (2.1.1) lib/better_errors/middleware.rb:84:in `protected_app_call'
better_errors (2.1.1) lib/better_errors/middleware.rb:79:in `better_errors_call'
better_errors (2.1.1) lib/better_errors/middleware.rb:57:in `call'
actionpack (4.1.6) lib/action_dispatch/middleware/debug_exceptions.rb:17:in `call'
actionpack (4.1.6) lib/action_dispatch/middleware/show_exceptions.rb:30:in `call'
railties (4.1.6) lib/rails/rack/logger.rb:38:in `call_app'
railties (4.1.6) lib/rails/rack/logger.rb:20:in `block in call'
activesupport (4.1.6) lib/active_support/tagged_logging.rb:68:in `block in tagged'
activesupport (4.1.6) lib/active_support/tagged_logging.rb:26:in `tagged'
activesupport (4.1.6) lib/active_support/tagged_logging.rb:68:in `tagged'
railties (4.1.6) lib/rails/rack/logger.rb:20:in `call'
actionpack (4.1.6) lib/action_dispatch/middleware/request_id.rb:21:in `call'
rack (1.5.2) lib/rack/methodoverride.rb:21:in `call'
rack (1.5.2) lib/rack/runtime.rb:17:in `call'
activesupport (4.1.6) lib/active_support/cache/strategy/local_cache_middleware.rb:26:in `call'
rack (1.5.2) lib/rack/lock.rb:17:in `call'
actionpack (4.1.6) lib/action_dispatch/middleware/static.rb:64:in `call'
rack (1.5.2) lib/rack/sendfile.rb:112:in `call'
railties (4.1.6) lib/rails/engine.rb:514:in `call'
railties (4.1.6) lib/rails/application.rb:144:in `call'
rack (1.5.2) lib/rack/lock.rb:17:in `call'
rack (1.5.2) lib/rack/content_length.rb:14:in `call'
rack (1.5.2) lib/rack/handler/webrick.rb:60:in `service'
/Users/masah/.rbenv/versions/2.1.4/lib/ruby/2.1.0/webrick/httpserver.rb:138:in `service'
/Users/masah/.rbenv/versions/2.1.4/lib/ruby/2.1.0/webrick/httpserver.rb:94:in `run'
/Users/masah/.rbenv/versions/2.1.4/lib/ruby/2.1.0/webrick/server.rb:295:in `block in start_thread'a

よろしくお願いします。