Create sdg manager

db/migrate/20201124145559_create_sdg_manager.rb

@@ -0,0 +1,8 @@
+class CreateSDGManager < ActiveRecord::Migration[5.2]
+  def change
+    create_table :sdg_managers do |t|
+      t.belongs_to :user, foreign_key: true, index: { unique: true }
+      t.timestamps
+    end
+  end
+end