add input method CANGJIE in ubuntu 17.04

$ sudo apt-get install ibus-cangjie ibus-cangjie3
$ ibus restart

# my choice using version 3
click "System Settings" > "Language Support" > "Chinese (Cangjie3)"

# check text input with 'ibus' selected

# to activate
#  +

ref: https://askubuntu.com/questions/59356/how-do-i-get-chinese-input-to-work