Removed pg_dump usage in postgres in favor of normal SQL queries

[emilpriver]

This PR removes the usage of pg_dump and replaces it with normal sql queries.

This code generates something like this:

--
-- SQL Schema dump automatic generated by geni
--


-- EXTENSIONS

CREATE EXTENSION IF NOT EXISTS "uuid-ossp" WITH SCHEMA public;

-- TABLES
-- EXTENSIONS

CREATE EXTENSION IF NOT EXISTS "uuid-ossp" WITH SCHEMA public;

-- TABLES

CREATE TABLE schema_migrations (
 id character varying (255) NOT NULL
);

CREATE TABLE table_1 (
 name character varying (255) NOT NULL
);

CREATE TABLE table_2 (
 id integer  NOT NULL,
 name character varying (255) NOT NULL,
 created_at timestamp without time zone
);

-- VIEWS

CREATE VIEW brazil AS\n SELECT table_2.name
   FROM table_2
  WHERE (table_2.id = 2);;

-- CONSTRAINTS

ALTER TABLE schema_migrations ADD CONSTRAINT schema_migrations_pkey PRIMARY KEY (id);

ALTER TABLE table_2 ADD CONSTRAINT employee_unq UNIQUE (name);

ALTER TABLE table_2 ADD CONSTRAINT table_2_pkey PRIMARY KEY (id);

-- INDEXES

CREATE UNIQUE INDEX employee_unq ON public.table_2 USING btree (name)

CREATE UNIQUE INDEX schema_migrations_pkey ON public.schema_migrations USING btree (id)

CREATE UNIQUE INDEX table_2_pkey ON public.table_2 USING btree (id)

-- COMMENTS

COMMENT ON COLUMN table_2.id IS comment text;

Closes #33