Move alembic part in refstack/db/migrations

Make preparation for future encapsulation database logic
and best structurisation of RefStack project.
Move alembic related part in refstack/db/migrations.

Change-Id: I8e35e6d78227a4e901dcbf85bb7dc56211688a52

doc/refstack.md

@@ -24,6 +24,8 @@ Update the "app_address" parameter in the config.json file to the correct addres
 
 Setup or update the database
 
+`cd refstack/db/migrations`
+
 NOTE: you are going to have to modify the db connection string in `alembic.ini` to get this working
 
 PROTIP: if you just want to test this out, use `-n alembic_sqlite` to make a local sqlite db

refstack/db/migrations/alembic/env.py

@@ -15,8 +15,7 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 from __future__ import with_statement
-import sys
-sys.path.append("./")
+
 from alembic import context
 from sqlalchemy import engine_from_config, pool