add a organization table (addresses #40)

* development.ini:
  - change testing database to PostgreSQL
  - set required database version to 4
 * data/dbrepo/versions/004_Add_organization_table.py:
  - create/drop organization table
  - add organizationid foreign key reference to client table
 * gnuviechadmin/backend/tables.py:
  - add reflected organization_table

data/dbrepo/versions/004_Add_organization_table.py

@@ -0,0 +1,29 @@
+from sqlalchemy import MetaData, Table, Column, Integer, Unicode, ForeignKey
+from migrate import migrate_engine
+from migrate.changeset.schema import create_column
+from gnuviechadmin.config import config
+
+dbschema = None
+if 'database.schema' in config:
+    dbschema = config['database.schema']
+
+meta = MetaData(migrate_engine)
+client = Table('client', meta, schema = dbschema, autoload = True)
+organization = Table(
+    'organization', meta,
+    Column('organizationid', Integer, primary_key = True),
+    Column('name', Unicode(200), nullable = False, unique = True),
+    schema = dbschema,
+    useexisting = True)
+
+def upgrade():
+    organization.create()
+    col = Column('organizationid', Integer,
+                 ForeignKey(organization.c.organizationid),
+                 nullable = True)
+    create_column(col, client)
+
+
+def downgrade():
+    client.c.organizationid.drop()
+    organization.drop()