Update teacher.sql (#8)

Author: zchpeter

schema/teacher.sql

@@ -3,6 +3,5 @@ CREATE TABLE "public"."teacher" (
     "first_name" text NOT NULL,
     "last_name" text NOT NULL,
     "email" text NOT NULL,
-    "phone" text NOT NULL,
     CONSTRAINT "teacher_pkey" PRIMARY KEY (student_no)
 );