Adds migration path from pre-release database to stable (previously unsupported) (#586)

eos/db/migrations/upgrade14.py

@@ -0,0 +1,19 @@
+"""
+Migration 14
+
+- This should take care of issue #586.
+"""
+
+import sqlalchemy
+
+def upgrade(saveddata_engine):
+    if saveddata_engine.execute("SELECT name FROM sqlite_master WHERE type='table' AND name='fighters'").scalar() == 'fighters':
+        # Fighters table exists
+        try:
+            saveddata_engine.execute("SELECT active FROM fighters LIMIT 1")
+        except sqlalchemy.exc.DatabaseError:
+            # if we don't have the active column, we are on an old pre-release version. Drop the tables and move on
+            # (they will be recreated)
+
+            saveddata_engine.execute("DROP TABLE fighters")
+            saveddata_engine.execute("DROP TABLE fightersAbilities")