diff --git a/docker-compose.yml b/docker-compose.yml
index 26db95d..b45a374 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -1,12 +1,19 @@
 version: "2"
 
 services:
+ web:
+  image: docker.clkl.de/partdoc/web:0.1
+  build: partdoc
+  env_file: postgres.env
+  volumes:
+   - ./partdoc/:/app/
+   - ./sketches/:/app/sketches/
+  working_dir: /app
+  command: python3 ./manage.py runserver 0.0.0.0:8000
+  ports:
+   - 8080:8000
  db:
   image: postgres:10-alpine
   volumes:
    - ./pgdata/:/var/lib/postgresql/data/
-  environment:
-   - POSTGRES_PASSWORD=secret
-   - POSTGRES_USER=partdoc
-  ports:
-   - "127.0.0.1:5432:5432"
\ No newline at end of file
+  env_file: postgres.env
\ No newline at end of file
diff --git a/partdoc/Dockerfile b/partdoc/Dockerfile
new file mode 100644
index 0000000..50bdd2c
--- /dev/null
+++ b/partdoc/Dockerfile
@@ -0,0 +1,6 @@
+FROM alpine:3.7
+
+ADD requirements.txt /
+RUN apk add --update --no-cache python3 py3-psycopg2 && \
+	sed -i 's/psycopg2/#psycopg2/' /requirements.txt && \
+	pip3 install -r /requirements.txt && rm /requirements.txt
\ No newline at end of file
diff --git a/partdoc/partdoc/settings.py b/partdoc/partdoc/settings.py
index 72bd233..bd524b1 100644
--- a/partdoc/partdoc/settings.py
+++ b/partdoc/partdoc/settings.py
@@ -36,7 +36,7 @@ INSTALLED_APPS = [
 	'django.contrib.sessions',
 	'django.contrib.messages',
 	'django.contrib.staticfiles',
-	'django_extensions',
+	#'django_extensions',
 ]
 
 MIDDLEWARE = [
@@ -75,11 +75,11 @@ WSGI_APPLICATION = 'partdoc.wsgi.application'
 DATABASES = {
 	'default': {
 		'ENGINE': 'django.db.backends.postgresql',
-		'NAME': 'partdoc',
-		'USER': 'partdoc',
-		'PASSWORD': 'secret',
-		'HOST': '127.0.0.1',
-		'PORT': '5432',
+		'NAME': os.environ.get('POSTGRES_USER',os.environ.get('POSTGRES_DB','postgres')),
+		'USER': os.environ.get('POSTGRES_USER','postgres'),
+		'PASSWORD': os.environ.get('POSTGRES_PASSWORD',''),
+		'HOST': os.environ.get('DB_HOST','db'),
+		'PORT': os.environ.get('DB_PORT','5432'),
 	}
 }
 
@@ -121,3 +121,19 @@ STATIC_URL = '/static/'
 STATIC_ROOT = 'static/'
 
 DATA_UPLOAD_MAX_NUMBER_FIELDS = 10000
+
+LOGGING = {
+    'version': 1,
+    'disable_existing_loggers': False,
+    'handlers': {
+        'console': {
+            'class': 'logging.StreamHandler',
+        },
+    },
+    'loggers': {
+        'django': {
+            'handlers': ['console'],
+            'level': os.getenv('DJANGO_LOG_LEVEL', 'INFO'),
+        },
+    },
+}
diff --git a/partdoc/parts/models.py b/partdoc/parts/models.py
index 1c8370d..931ce3c 100644
--- a/partdoc/parts/models.py
+++ b/partdoc/parts/models.py
@@ -59,6 +59,23 @@ class Version(PartModel):
 
 	def __str__(self):
 		return "Version: " + self.name + " (" + str(self.product) + ")"
+		
+	@staticmethod		
+	@transaction.atomic
+	def merge(target, rip):
+		self = Version.objects.filter(name=target)
+		other = Version.objects.filter(name=rip)
+		if not (self and other):
+			raise ValueError("invalid arguments! {} {}".format(self, other))
+		self = self.first()
+		other = other.first()
+		for x in other.introduces.all():
+			x.used_until = self
+			x.save()
+		for x in other.dissmisses.all():
+			x.used_since = self
+			x.save()
+		other.delete()
 
 
 class Part(PartModel):
@@ -129,8 +146,8 @@ class ProductUsage(PartModel):
 	quantity = models.IntegerField(null=True)
 	on_demand = models.BooleanField(default=False)
 	obsolete = models.BooleanField(default=False)
-	used_until = models.ForeignKey(Version, null=True, blank=True, related_name='introduces', on_delete=models.SET_NULL)
-	used_since = models.ForeignKey(Version, null=True, blank=True, related_name='dissmisses', on_delete=models.SET_NULL)
+	used_until = models.ForeignKey(Version, null=True, blank=True, related_name='introduces', on_delete=models.SET_NULL) # TODO: switch 'introduces' and 'dismisses'
+	used_since = models.ForeignKey(Version, null=True, blank=True, related_name='dissmisses', on_delete=models.SET_NULL) # TODO: switch 'introduces' and 'dismisses'
 	# replaced_by = models.ForeignKey('self', null=True, blank=True, related_name='replaces', on_delete=models.SET_NULL)
 	replaced_by = models.CharField(max_length=512, null=True, blank=True)
 	# alternative = models.ForeignKey('self', null=True, blank=True, related_name='alternatives', on_delete=models.SET_NULL)
diff --git a/partdoc/parts/views.py b/partdoc/parts/views.py
index 7d561b3..cc523af 100644
--- a/partdoc/parts/views.py
+++ b/partdoc/parts/views.py
@@ -111,8 +111,7 @@ def sketch_add(request, product_id, sketch_id=None):
 		if len(note):
 			prod.note = note
 		if len(replaced):
-			# replacement, _ = ProductUsage.objects.get_or_create(product=product, usage__part__number=replaced)
-			# prod.replaced_by = replacement
+			prod.replaced_by = replaced
 			prod.note += "{REP:" + str(replaced) + "}"  # TODO
 		internal = request.POST.getlist('internal')[i]
 		if len(internal):
diff --git a/partdoc/requirements.txt b/partdoc/requirements.txt
index d7dc9da..5a39390 100644
--- a/partdoc/requirements.txt
+++ b/partdoc/requirements.txt
@@ -1,3 +1,2 @@
 django==2.0.1
 psycopg2==2.7.3.2
-django-extensions==1.9.9
diff --git a/postgres.env b/postgres.env
new file mode 100644
index 0000000..4961967
--- /dev/null
+++ b/postgres.env
@@ -0,0 +1,4 @@
+POSTGRES_PASSWORD=secret
+POSTGRES_USER=partdoc
+
+PYTHONUNBUFFERED=1
\ No newline at end of file