Drop staff table

We are dropping the staff table because there
is no model related to the table and it isn't being
used for anything in our application.

db/migrate/20170405230953_drop_staff.rb

@@ -0,0 +1,5 @@
+class DropStaff < ActiveRecord::Migration[5.0]
+  def change
+    drop_table :staff
+  end
+end

db/schema.rb

@@ -69,15 +69,6 @@
     t.datetime "updated_at", null: false
   end
 
-  create_table "staff", force: :cascade do |t|
-    t.string   "pod"
-    t.date     "started_at_company"
-    t.integer  "person_id"
-    t.datetime "created_at",         null: false
-    t.datetime "updated_at",         null: false
-    t.index ["person_id"], name: "index_staff_on_person_id"
-  end
-
   create_table "topic_requests", force: :cascade do |t|
     t.string   "name",       null: false
     t.datetime "created_at", null: false