Provision DynamoDb with serverless.yml

More details to here: https://www.serverless.com/dynamodb

resources:
  Resources:
    companies:
      Type: AWS::DynamoDB::Table
      Properties:
        TableName: companies
        AttributeDefinitions:
          - AttributeName: gasSafeNumber
            AttributeType: S
        KeySchema:
          - AttributeName: gasSafeNumber
            KeyType: HASH
        ProvisionedThroughput:
          ReadCapacityUnits: 3
          WriteCapacityUnits: 3