:sparkles: added zip code seed data and migrations

backend/db/migrations/20210929163630_zipcodes.js

@@ -0,0 +1,14 @@
+exports.up = function (knex) {
+    return knex.schema.createTable('zip_codes', function (table) {
+        table.integer('zip_code_id').primary()
+        table.string('latitude', 16).notNullable()
+        table.string('longitude', 16).notNullable()
+        table.string('city', 128).notNullable()
+        table.string('state', 16).notNullable()
+        table.string('county', 128).notNullable()
+    })
+}
+
+exports.down = function (knex) {
+    return knex.schema.dropTable('zip_codes')
+}

backend/db/seeds/08-zipcodes.js

@@ -0,0 +1,11 @@
+const zips = require('../zipcodes')
+
+exports.seed = function (knex) {
+    // Deletes ALL existing entries
+    return knex('zip_codes')
+        .truncate()
+        .then(function () {
+            // Inserts seed entries
+            return knex('zip_codes').insert(zips)
+        })
+}