code: function createSchema(db) {
      var docStore = db.createObjectStore(DOC_STORE, {keyPath : 'id'});
      db.createObjectStore(BY_SEQ_STORE, {autoIncrement: true})
        .createIndex('_doc_id_rev', '_doc_id_rev', {unique: true});
      db.createObjectStore(ATTACH_STORE, {keyPath: 'digest'});
      db.createObjectStore(META_STORE, {keyPath: 'id', autoIncrement: false});
      db.createObjectStore(DETECT_BLOB_SUPPORT_STORE);
  
      // added in v2
      docStore.createIndex('deletedOrLocal', 'deletedOrLocal', {unique : false});
  
      // added in v3
      db.createObjectStore(LOCAL_STORE, {keyPath: '_id'});
  
      // added in v4
      var attAndSeqStore = db.createObjectStore(ATTACH_AND_SEQ_STORE,
        {autoIncrement: true});
      attAndSeqStore.createIndex('seq', 'seq');
      attAndSeqStore.createIndex('digestSeq', 'digestSeq', {unique: true});
    }
docs: called when creating a fresh new database