Add trusted application functionality (#533)

* Add trusted application functionality

This lets users apply for trusted status, given certain minimum
requirements. Moderators can then review the applications, giving
a recommendation, and administrators can accept or reject them.

If an application is accepted or rejected, the user receives an
e-mail about it.

Markdown images are not rendered in applications to prevent browsers
from sending automatic requests to untrusted webservers.

Users who have had their application rejected cannot re-apply for a set
amount of days.

* minor fixes

migrations/versions/5cbcee17bece_add_trusted_applications.py

@@ -0,0 +1,47 @@
+"""Add trusted applications
+
+Revision ID: 5cbcee17bece
+Revises: 8a6a7662eb37
+Create Date: 2018-11-05 15:16:07.497898
+
+"""
+from alembic import op
+import sqlalchemy as sa
+import sqlalchemy_utils
+
+
+# revision identifiers, used by Alembic.
+revision = '5cbcee17bece'
+down_revision = '8a6a7662eb37'
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    op.create_table('trusted_applications',
+    sa.Column('id', sa.Integer(), nullable=False),
+    sa.Column('submitter_id', sa.Integer(), nullable=False, index=True),
+    sa.Column('created_time', sa.DateTime(), nullable=True),
+    sa.Column('closed_time', sa.DateTime(), nullable=True),
+    sa.Column('why_want', sa.String(length=4000), nullable=False),
+    sa.Column('why_give', sa.String(length=4000), nullable=False),
+    sa.Column('status', sa.Integer(), nullable=False),
+    sa.ForeignKeyConstraint(['submitter_id'], ['users.id'], ),
+    sa.PrimaryKeyConstraint('id')
+    )
+    op.create_table('trusted_reviews',
+    sa.Column('id', sa.Integer(), nullable=False),
+    sa.Column('reviewer_id', sa.Integer(), nullable=False),
+    sa.Column('app_id', sa.Integer(), nullable=False),
+    sa.Column('created_time', sa.DateTime(), nullable=True),
+    sa.Column('comment', sa.String(length=4000), nullable=False),
+    sa.Column('recommendation', sa.Integer(), nullable=False),
+    sa.ForeignKeyConstraint(['app_id'], ['trusted_applications.id'], ),
+    sa.ForeignKeyConstraint(['reviewer_id'], ['users.id'], ),
+    sa.PrimaryKeyConstraint('id')
+    )
+
+
+def downgrade():
+    op.drop_table('trusted_reviews')
+    op.drop_table('trusted_applications')