diff --git a/.gitignore b/.gitignore
index af3a38a..a217e90 100644
--- a/.gitignore
+++ b/.gitignore
@@ -12,3 +12,6 @@ wheels/
 # Local application data
 log/
 *.db
+
+# Gradle
+local.properties
diff --git a/app.py b/backend/app.py
similarity index 100%
rename from app.py
rename to backend/app.py
diff --git a/db.py b/backend/db.py
similarity index 100%
rename from db.py
rename to backend/db.py
diff --git a/dto.py b/backend/dto.py
similarity index 100%
rename from dto.py
rename to backend/dto.py
diff --git a/init-db.py b/backend/init-db.py
similarity index 97%
rename from init-db.py
rename to backend/init-db.py
index b591a44..1c5cadd 100644
--- a/init-db.py
+++ b/backend/init-db.py
@@ -16,6 +16,7 @@ cur.execute("CREATE TABLE devices(access_key, secret_key_hash, type, name)")
 # type                : INCOMING, OUTGOING
 # local_phone_number  : a SECONDARY device SIM's phone number
 # remote_phone_number : a phone number or shortcode of the other party
+# TODO add column for sender's access key
 cur.execute("CREATE TABLE messages(content, ts_received, ts_sent, type, local_phone_number, remote_phone_number)")
 cur.execute("CREATE TABLE sim_events(sim_id, ts, note, cost, currency)")
 cur.execute("CREATE TABLE sim_cards(phone_number, device_access_key)")
diff --git a/run.sh b/backend/run.sh
similarity index 100%
rename from run.sh
rename to backend/run.sh