r0.3.21

1. add requirement package: requests
2. ticket list api's response add workflow_info field

r0.3.20

1. models inheritance and ticket detail api add is_end field value
2. bugfix: new state and edit state api return wrong arg issue
3. alter the length of ticket's title field from 50 to 500
4. bugfix: only run the first notice task when config more then one
5. ticket list api optimize
6. optimize init_state api's serialize logic

r0.3.19

1. ticket detail api add attr: ticket's id
2. transitions api add attr: transitions's attribute_type_id
3. add new api: get ticket's participant info

r0.3.18

1. ticket detail api's performance optimization
2. alter doc link url for guide documentation

r0.3.17

1. support new participant type: hook

r0.3.16

bugfix: for STATE_DISTRIBUTE_TYPE_ALL exception

r0.3.15

1. optimization: ticket list api do not return -1 code when some creator is not existed in user table
2. bugfix: return wrong arg in delete state api

r0.3.14

1. ticket list api add creator's department info
2. ticket detail api add creator's department info

r0.3.13

1. bugfix: ticket transitions api return -1 code when has no permission
2. ticket list api add is_end info

r0.3.12

1. bugfix: create or handle ticket fail when there are some optional field in the ticket detail form and user set the field none value
2. optimize: parameter type checking in new ticket api