chore: Add controllers for conversation participants (#6462)

Co-authored-by: Aswin Dev P.S <aswindevps@gmail.com>
Co-authored-by: Sojan Jose <sojan@chatwoot.com>

db/migrate/20220808193420_add_conversation_participants.rb

@@ -0,0 +1,11 @@
+class AddConversationParticipants < ActiveRecord::Migration[6.1]
+  def change
+    create_table 'conversation_participants', force: :cascade do |t|
+      t.references :account, null: false
+      t.references :user, null: false
+      t.references :conversation, null: false
+      t.datetime 'created_at', precision: 6, null: false
+      t.datetime 'updated_at', precision: 6, null: false
+    end
+  end
+end

db/migrate/20230118155353_add_unique_index_to_conversation_participants.rb

@@ -0,0 +1,5 @@
+class AddUniqueIndexToConversationParticipants < ActiveRecord::Migration[6.1]
+  def change
+    add_index :conversation_participants, [:user_id, :conversation_id], unique: true
+  end
+end

db/schema.rb

@@ -388,6 +388,18 @@ ActiveRecord::Schema.define(version: 2023_02_09_033203) do
     t.index ["phone_number", "account_id"], name: "index_contacts_on_phone_number_and_account_id"
   end
 
+  create_table "conversation_participants", force: :cascade do |t|
+    t.bigint "account_id", null: false
+    t.bigint "user_id", null: false
+    t.bigint "conversation_id", null: false
+    t.datetime "created_at", precision: 6, null: false
+    t.datetime "updated_at", precision: 6, null: false
+    t.index ["account_id"], name: "index_conversation_participants_on_account_id"
+    t.index ["conversation_id"], name: "index_conversation_participants_on_conversation_id"
+    t.index ["user_id", "conversation_id"], name: "index_conversation_participants_on_user_id_and_conversation_id", unique: true
+    t.index ["user_id"], name: "index_conversation_participants_on_user_id"
+  end
+
   create_table "conversations", id: :serial, force: :cascade do |t|
     t.integer "account_id", null: false
     t.integer "inbox_id", null: false