Merge branch 'release/1.0.18' into develop
Merge pull request #42 from praekelt/master

Merge branch 'release/1.0.18'
Added database field for textbook link
Added field
Merge pull request #43 from praekelt/feature/issue-29-add-textbook-link

Feature/issue 29 add textbook link
Update version number
Merge branch 'release/1.0.19'