PAN-52 Fixed issue with the Theorems API

persistence/scripts/mysql/local_development.sql

@@ -41,7 +41,6 @@ CREATE TABLE proofs
   proof VARCHAR(4096) NOT NULL,
   branch    VARCHAR(512) NOT NULL,
   theorem   INT NOT NULL,
-  FOREIGN KEY fk_theorem (theorem) REFERENCES theorems (id) ON DELETE NO ACTION ON UPDATE NO ACTION,
   referenced_definitions JSON,
   referenced_theorems JSON,
   date_added DATE,