Replace all db.String with db.Text

Text is as efficient in Postgres and is recommended over varchar.
It avoids having to put an arbitrary max length to strings.

app/models.py

@@ -76,7 +76,7 @@ usergroups_table = db.Table(
 
 class Group(db.Model):
     id = db.Column(db.Integer, primary_key=True)
-    name = db.Column(db.String(100), nullable=False, unique=True)
+    name = db.Column(db.Text, nullable=False, unique=True)
 
     def __init__(self, name):
         self.name = name
@@ -97,9 +97,9 @@ class User(db.Model, UserMixin):
     __tablename__ = 'user_account'
 
     id = db.Column(db.Integer, primary_key=True)
-    username = db.Column(db.String(50), unique=True)
-    name = db.Column(db.String(100))
-    email = db.Column(db.String(100))
+    username = db.Column(db.Text, unique=True)
+    name = db.Column(db.Text)
+    email = db.Column(db.Text)
     grp = db.relationship('Group', secondary=usergroups_table,
                           backref=db.backref('members', lazy='dynamic'))
     # Proxy the 'name' attribute from the 'grp' relationship
@@ -200,8 +200,8 @@ class Item(db.Model):
     id = db.Column(db.Integer, primary_key=True)
     _created = db.Column(db.DateTime, default=db.func.now())
     _updated = db.Column(db.DateTime, default=db.func.now(), onupdate=db.func.now())
-    ics_id = db.Column(db.String(6), unique=True, index=True)
-    serial_number = db.Column(db.String(100), nullable=False)
+    ics_id = db.Column(db.Text, unique=True, index=True)
+    serial_number = db.Column(db.Text, nullable=False)
     manufacturer_id = db.Column(db.Integer, db.ForeignKey('manufacturer.id'))
     model_id = db.Column(db.Integer, db.ForeignKey('model.id'))
     location_id = db.Column(db.Integer, db.ForeignKey('location.id'))