here come the tags

app/controllers/clips_controller.rb

@@ -15,6 +15,13 @@ class ClipsController < ApplicationController
   def create
     @clip = Clip.new(clip_params)
     if @clip.save
+      params[:clip][:tag_ids].each do |tag_id|
+        unless tag_id.empty?
+          tag = Tag.find(tag_id)
+          @clip.tags << tag
+        end
+      end
+
       redirect_to @clip
     else
       render :new, status: :unprocessable_entity
@@ -24,8 +31,25 @@ class ClipsController < ApplicationController
   def edit
   end
 
-  def update
+  def update    
     if @clip.update(clip_params)
+      newtags = []
+      params[:clip][:tag_ids].each do |tag_id|
+        unless tag_id.empty?
+          tag = Tag.find(tag_id)
+          newtags.push(tag)
+          unless @clip.tags.include? tag
+            @clip.tags << tag
+          end 
+        end
+      end
+
+      @clip.tags.each do |tag|
+        unless newtags.include? tag
+          @clip.tags.delete tag
+        end
+      end
+
       redirect_to @clip
     else
       render :edit, status: :unprocessable_entity

app/helpers/tag_to_clips_helper.rb

@@ -0,0 +1,2 @@
+module TagToClipsHelper
+end

app/models/clip.rb

@@ -1,5 +1,7 @@
 class Clip < ApplicationRecord
   has_one_attached :video
   belongs_to :category
+  has_many :tag_to_clips
+  has_many :tags, through: :tag_to_clips
   validates :title, presence: true
 end

app/models/tag.rb

@@ -0,0 +1,4 @@
+class Tag < ApplicationRecord
+  has_many :tag_to_clips
+  has_many :clips, through: :tag_to_clips
+end

app/models/tag_to_clip.rb

@@ -0,0 +1,4 @@
+class TagToClip < ApplicationRecord
+  belongs_to :clip
+  belongs_to :tag
+end

app/views/clips/_form.html.erb

@@ -4,6 +4,7 @@
     <%= form.text_field :title %>
     <%= form.file_field :video, :accept => 'video/quicktime,video/mp4' %>
     <%= form.select :category_id, Category.all.collect{ |t| [ t.name, t.id ] }%>
+    <%= collection_select(:clip, :tag_ids, Tag.all, :id, :name, {}, { :multiple => true } )%>
   </div>
 
   <div>

app/views/clips/show.html.erb

@@ -2,6 +2,7 @@
   <h1><%= @clip.title %></h1>
 <% end %>
 <b>Category:</b> <%= link_to @clip.category.name, @clip.category %><br>
+<b>Tags:</b> <%= @clip.tags.map(&:name).join(', ') %><br>
 <% if @clip.video.attached? %>
 <%= video_tag @clip.video, :controls => true%>
 <% end %>