update notes, mainly focus on the design of notice board, and the 2nd leg calculation
add a flatpages as a notice board. default.html in tepmlates/flatpages/ is created.
update the structure of templates/flatpages/default.html
update the structure of templates/flatpages/default.html
update TODO.md
bug fix on missing load staticfiles
add a field market_reference_price in Topic model
override the save() method, in order to trim  whitespace of title
override the save() method in Topic and Source models, in order to trim  whitespace of title
turn on market_reference_price in admin
update README.md & TODO.md
import the ValitationError in model
cancel the default value in the campagin field in Topic model
migrate the previous edited help_text in models
explain why no default=1 in the campagin of Topic model
reorder the fields of Source model in admin
reorder the fields of Source model in model too