Added explanation how to create extensions inside ga_propagation database.

Author: fs191

README.md

@@ -17,6 +17,8 @@ If PostgreSQL has not been installed yet, it needs to be done before running. Th
 
 After PostgreSQL has been installed, it is necessary to create a database that will be used by the tool. For compatibility with pleak-backend, the database name should be 'ga_propagation'. Permissions on 'ga_propagation' should be given to the user 'ga_propagation', whose password is the same as used inside "pleak-tools/pleak-backend/src/main/java/com/naples/rest/GuessingAdvantageService.java", which is 'ceec4eif7ya' by default. If any other database or user names are used, they should be changed in "GuessingAdvantageService.java" as well. Here is an example of how to do it with Ubuntu system:
 
+1. Create the ga_propagation user.
+
     USERNAME@xxxx:~$ sudo -u postgres -i
     (prompts USERNAME's password)
     postgres@xxxx:~$ createuser --interactive --pwprompt
@@ -27,10 +29,19 @@ After PostgreSQL has been installed, it is necessary to create a database that w
     Shall the new role be allowed to create databases? (y/n) n
     Shall the new role be allowed to create more new roles? (y/n) n
 
+2. Create the ga_propagation database.
+
     postgres@xxxx:~$ psql
     postgres=# create database ga_propagation;
     CREATE DATABASE
-    USERNAME=# \q
+    postgres=# \c ga_propagation
+    You are now connected to database "ga_propagation" as user "postgres".
+
+    ga_propagation=# create extension cube;
+    CREATE EXTENSION
+    ga_propagation=# create extension earthdistance;
+    CREATE EXTENSION
+    ga_propagation=# \q
 
 The tool assumes that the contents of input tables are uploaded to the database by some other application. The example runs will fail if there is no suitable data, i.e. no tables specified in the input schema file.