Adds a configuration flag to enable create_table on save

lib/dynamoid/config.rb

@@ -59,6 +59,7 @@ module Config
     option :http_idle_timeout, default: nil     #                                                  - default: 5
     option :http_open_timeout, default: nil     #                                                  - default: 15
     option :http_read_timeout, default: nil     #                                                  - default: 60
+    option :create_table_on_save, default: true
 
     # The default logger for Dynamoid: either the Rails logger or just stdout.
     #

lib/dynamoid/persistence.rb

@@ -507,7 +507,10 @@ def persisted?
     # @return [true|false] Whether saving successful or not
     # @since 0.2.0
     def save(options = {})
-      self.class.create_table(sync: true)
+      if Dynamoid.config.create_table_on_save
+        self.class.create_table(sync: true)
+      end
+
       create_or_update = new_record? ? :create : :update
 
       run_callbacks(:save) do

spec/dynamoid/persistence_spec.rb

@@ -2293,6 +2293,53 @@ def around_update_callback
       end.not_to change { obj.class.count }
     end
 
+    context 'when disable_create_table_on_save is false' do
+      before do
+        Dynamoid.configure do |config|
+          @original_create_table_on_save = config.create_table_on_save
+          config.create_table_on_save = false
+        end
+      end
+
+      after do
+        Dynamoid.configure do |config|
+          config.create_table_on_save = @original_create_table_on_save
+        end
+      end
+
+      it 'raises Aws::DynamoDB::Errors::ResourceNotFoundException error' do
+        model = klass.new
+
+        expect(klass).not_to receive(:create_table)
+
+        expect { model.save! }.to raise_error(Aws::DynamoDB::Errors::ResourceNotFoundException)
+      end
+    end
+
+    context 'when disable_create_table_on_save is false and the table exists' do
+      before do
+        Dynamoid.configure do |config|
+          @original_create_table_on_save = config.create_table_on_save
+          config.create_table_on_save = false
+        end
+        klass.create_table
+      end
+
+      after do
+        Dynamoid.configure do |config|
+          config.create_table_on_save = @original_create_table_on_save
+        end
+      end
+
+      it 'persists the model' do
+        obj = klass.new(name: 'John')
+        obj.save
+
+        expect(klass.exists?(obj.id)).to eq true
+        expect(klass.find(obj.id).name).to eq 'John'
+      end
+    end
+
     describe 'partition key value' do
       it 'generates "id" for new model' do
         obj = klass.new