add models to feature/transaction. Models include algorithm of some necessary functions
edit transaction models, replace some algorithm with codes
Merge branch 'master' into feature/transaction after merging feature/reputation into master

Conflicts:
	bookshare/settings/base.py
finish transaction models
add views, serializers, urls to feature/transaction
modify transaction models
add custom manager to models
edit transaction model syntax and rename transaction model method
change design of transaction.borrower from user to membership
edit style of coding, improve naming of attribute
Merge branch 'master' of github.com:9gix/bsapi into feature/transaction
Initial Migrations
Merge branch 'master' of https://github.com/9gix/bsapi into feature/transaction
Merge branch 'feature/transaction' of https://github.com/9gix/bsapi into feature/transaction
Merge pull request #4 from 9gix/feature/transaction

Feature/transaction