diff --git a/app/database/models.py b/app/database/models.py
index 3f433a0..a8186f6 100644
--- a/app/database/models.py
+++ b/app/database/models.py
@@ -1,4 +1,3 @@
-import enum
 from datetime import datetime
 
 from pytz import timezone
@@ -52,9 +51,7 @@ def __repr__(self):
         return '<Library %r>' % self.name
 
 
-class SessionEnum(enum.Enum):
-    first = "09:00"
-    second = "10:00"
+session_time_choices = ["09:00", "10:00"]
 
 
 def now_at_seoul():
@@ -80,7 +77,8 @@ class Speaker(db.Model, TimestampMixin):
     password = db.Column(db.String(30), nullable=False)
     is_email_verified = db.Column(db.Boolean, default=False)
     email_sended_at = db.Column(db.DateTime, nullable=True)
-    session_time = db.Column(db.Enum(SessionEnum), nullable=False)
+    session_time = db.Column(db.Enum(*session_time_choices),
+                             nullable=False)
     library_id = db.Column(INTEGER(11, unsigned=True),
                            db.ForeignKey('Libraries.id'),
                            nullable=False)
diff --git a/migrations/versions/6c0fbb516dfd_.py b/migrations/versions/ba0d91c0bfc5_.py
similarity index 90%
rename from migrations/versions/6c0fbb516dfd_.py
rename to migrations/versions/ba0d91c0bfc5_.py
index 78c4e64..8a6b80e 100644
--- a/migrations/versions/6c0fbb516dfd_.py
+++ b/migrations/versions/ba0d91c0bfc5_.py
@@ -1,8 +1,8 @@
 """empty message
 
-Revision ID: 6c0fbb516dfd
+Revision ID: ba0d91c0bfc5
 Revises: ad3c95a8a551
-Create Date: 2018-04-11 23:34:31.356913
+Create Date: 2018-04-12 13:31:37.508738
 
 """
 from alembic import op
@@ -10,7 +10,7 @@
 from sqlalchemy.dialects import mysql
 
 # revision identifiers, used by Alembic.
-revision = '6c0fbb516dfd'
+revision = 'ba0d91c0bfc5'
 down_revision = 'ad3c95a8a551'
 branch_labels = None
 depends_on = None
@@ -28,7 +28,7 @@ def upgrade():
     sa.Column('password', sa.String(length=30), nullable=False),
     sa.Column('is_email_verified', sa.Boolean(), nullable=True),
     sa.Column('email_sended_at', sa.DateTime(), nullable=True),
-    sa.Column('session_time', sa.Enum('first', 'second', name='sessionenum'), nullable=False),
+    sa.Column('session_time', sa.Enum('09:00', '10:00'), nullable=False),
     sa.Column('library_id', mysql.INTEGER(display_width=11, unsigned=True), nullable=False),
     sa.ForeignKeyConstraint(['library_id'], ['Libraries.id'], ),
     sa.PrimaryKeyConstraint('id'),