added sign-up, tweaked jinja macro flashes and message display

app/forms.py

@@ -1,9 +1,27 @@
 from flask_wtf import FlaskForm
 from wtforms import StringField, PasswordField, BooleanField, SubmitField
-from wtforms.validators import DataRequired
+from wtforms.validators import ValidationError, DataRequired, EqualTo, Email
+from app.models import User
 
 class LoginForm(FlaskForm):
     username = StringField('Username', validators=[DataRequired()])
     password = PasswordField('Password', validators=[DataRequired()])
     remember_me = BooleanField('Remember Me')
-    submit = SubmitField('Sign in')
+    submit = SubmitField('Sign in')
+
+class RegistrationForm(FlaskForm):
+    username = StringField('Username', validators=[DataRequired()])
+    email = StringField('Email', validators=[DataRequired(), Email()])
+    password = PasswordField('Password', validators=[DataRequired()])
+    password2 = PasswordField('Repeat Password', validators=[DataRequired(), EqualTo('password')])
+    submit = SubmitField('Register')
+
+    def validate_username(self, username):
+        user = User.query.filter_by(username=username.data).first()
+        if user is not None:
+            raise ValidationError('That username is not available.')
+    
+    def validate_email(self, email):
+        user = User.query.filter_by(email=email.data).first()
+        if user is not None:
+            raise ValidationError('That email address is not available.')