Automatically create control table if it doesn't exists

README.md

@@ -58,17 +58,6 @@ alter table users
 add email varchar(256) not null;
 ```
 
-#### Prerequisites
-One table needs to be created for the database to make this work:
-
-```
-CREATE TABLE database_versions (
-  version varchar(32) not null,
-  is_active boolean not null default false,
-  creation_date timestamp not null default current_timestamp
-);
-```
-
 To do the actual migration, then just run:
 ```
 # ./db-upgrade [ENVIRONMENT NAME]

db-upgrade

@@ -8,6 +8,17 @@ fi
 
 source env/$DB_ENVIRONMENT.conf
 
+# Create the control table, if it doesn't exist
+cat <<-EOF | psql $PSQL_OPTS -d $DB_NAME
+BEGIN;
+CREATE TABLE IF NOT EXISTS database_versions (
+  version varchar(32) not null,
+  is_active boolean not null default false,
+  creation_date timestamp not null default current_timestamp
+);
+END;
+EOF
+
 function add-version() {
   psql $PSQL_OPTS -c "update database_versions set is_active = false where is_active = true" $DB_NAME
   psql $PSQL_OPTS -c "insert into database_versions (version, is_active) values ('$1', TRUE)" $DB_NAME