make database sqlite compatible.

db.py

@@ -5,10 +5,15 @@ from flask import current_app, g
 from flask.cli import with_appcontext
 
 
-def get_db():
+def get_db(mod_path=None):
     if 'db' not in g:
+        # provide modified path if is not None
+        if mod_path is None:
+            path=current_app.config["DATABASE_URI"]
+        else:
+            path=mod_path
         g.db = sqlite3.connect(
-            current_app.config["DATABASE_URI"],
+            path,
             detect_types=sqlite3.PARSE_DECLTYPES
         )
         g.db.row_factory = sqlite3.Row
@@ -21,18 +26,18 @@ def close_db(e=None):
     if db is not None:
         db.close()
 
-def init_db():
-    db = get_db()
-
-    with current_app.open_resource('schema.sql') as f:
-        db.executescript(f.read().decode('utf8'))
 
 @click.command('init-db')
 @with_appcontext
 def init_db_command():
     """Clear the existing data and create new tables."""
-    init_db()
-    click.echo('Initialized the database.')
+    path = "./users.db"
+    db = get_db(mod_path="users.db")
+
+    with current_app.open_resource('schema.sql') as f:
+        db.executescript(f.read().decode('utf8'))    
+        
+    click.echo('Initialized the database at %s. Copy it to the according directory.'% path)
 
 def init_app(app):
     app.teardown_appcontext(close_db)

schema.sql

@@ -1,5 +1,5 @@
 DROP TABLE IF EXISTS user;
-
+PRAGMA journal_mode=wal;
 CREATE TABLE user (
   id INTEGER PRIMARY KEY AUTOINCREMENT,
   username TEXT NOT NULL,