[Add View][UI] hide the keyboard when user press 'return' button (p.252-255)

1. connect UITextField delegate in .xib
2. implement method 'textFieldShouldReturn:'
[Add View] support App Delegate in AddViewController (p.248-249)
[Add View] implement method 'addItem', and add new beverage emtity to core data (p.250)

dump SQL database: (p.256-259)

1. open terminal, and goto iPhone Simulator Applications storage

   $ cd ~/Library/Application\ Support/iPhone\ Simulator/7.1/Applications

2. find out the folder which "ios-core-data-demo.app" store the data

   $ find . -type d -name "ios-core-data-demo.app"

   output > ./48624DF7-6B59-4574-9A14-28BFA218B3F9/ios-core-data-demo.app

3. goto Documents folder, there is 3 files here

  $ cd 48624DF7-6B59-4574-9A14-28BFA218B3F9/Documents/
  $ ls

  output >  ios_core_data_demo.sqlite     ios_core_data_demo.sqlite-wal     ios_core_data_demo.sqlite-shm

4. open ios_core_data_demo sqlite

   $ sqlite3 ios_core_data_demo.sqlite

   output >  SQLite version 3.7.13 2012-07-17 17:46:21
             Enter ".help" for instructions
             Enter SQL statements terminated with a ";"
             sqlite>

5. dump SQL, we can see 'title : Hello' and 'detail : World'

   sqlite> .dump

   output > PRAGMA foreign_keys=OFF;
            BEGIN TRANSACTION;
            CREATE TABLE ZBEVERAGE ( Z_PK INTEGER PRIMARY KEY, Z_ENT INTEGER, Z_OPT INTEGER, ZDETAIL VARCHAR, ZTITLE VARCHAR );
            INSERT INTO "ZBEVERAGE" VALUES(1,1,1,'World','Hello');
            CREATE TABLE Z_PRIMARYKEY (Z_ENT INTEGER PRIMARY KEY, Z_NAME VARCHAR, Z_SUPER INTEGER, Z_MAX INTEGER);
            INSERT INTO "Z_PRIMARYKEY" VALUES(1,'Beverage',0,1);
            CREATE TABLE Z_METADATA (Z_VERSION INTEGER PRIMARY KEY, Z_UUID VARCHAR(255), Z_PLIST BLOB);
            INSERT INTO "Z_METADATA" VALUES(1,'163C019E-F97E-4EBF-8EB6-D4D8C341F3A1',X'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');
            COMMIT;

6. exit sqlite3

   sqlite> .exit