Terms and conditions screen (#118)

* Terms and Conditions screen added

* missing fields

* SQL migration added

* terms.text: markdown to html on server side

* markdown field type added

* other minor changes

migrations/1527814550220-add-tx-terms-accepted.js

@@ -0,0 +1,14 @@
+var db = require('./db')
+
+exports.up = function (next) {
+  const sql = [
+    'alter table cash_in_txs add column terms_accepted boolean not null default false',
+    'alter table cash_out_txs add column terms_accepted boolean not null default false'
+  ]
+
+  db.multi(sql, next)
+}
+
+exports.down = function (next) {
+  next()
+}