Remove some db constraints to permit partial projects be imported
Create rake task to import users/projects/rewards
Stop requiring statement_file_url from projects

According to some data to be entered in the platform, there are cases
when there's no statement url (yet).
state_names has no required order
Add external id to projects table
OpenURI is already required by Rails
Confirm emails of autogenerated users
Merge pull request #811 from neighborly/im-import-projects-task

Import projects task