add unique indexes to tables columns that require unique values

https://osraav.atlassian.net/browse/OSRA-252
OSRA-252 #code-review
Merge pull request #158 from PurityControl/db_indexes

Sold!
OSRA-252 #Resolved
Add missing indexes to foreign keys
Merge pull request #161 from NikitaAvvakumov/foreign_key_indexes

Add missing indexes to foreign keys
OSRA-260 #resolve