Invalid Datomic URI without database name

For some reason there is no database name in the `DATOMIC_URI` in the template. This results in a failure to deploy the web application. The error can be seen in `/var/log/tomcat7/localhost.<date>.log`:
```
java.lang.IllegalArgumentException: :db.error/invalid-db-uri Invalid database URI datomic:ddb://eu-west-1/datomic_demo_staging/
```
Merge pull request #10 from ulsa/patch-9

Invalid Datomic URI without database name