FIELD OF THE INVENTION This invention relates to a pouch being disposable or re- usable to be used for warming baby food contained in pouches or bags. The invention particularly relates to a sealed plastic pouch with liquid inside containing the active ingredient sodium acetate. This pouch may be referred to as a gel warmer. This pouch contains a metal disc inside that is manipulated to create an exothermic reaction, heating the gel inside the pouch which in turn transfers heat to the food pouch or bag that is enveloped in the gel warmer. The transference of heat from the gel pouch to the baby food pouch enables the food to be served at an appropriate temperature for babies. Thus the pouch described provides a caregiver a solution to warm baby without the use of batteries, electricity or other energy devices. BACKGROUND AND SUMMARY An exothermic reaction that provides an alternative to calcium oxide is disclosed on U.S. Pat. No. 4,522,190 to Kuhn et al., which discloses a heater material for use in heating food. Another invention using an exothermic reaction is disclosed in U.S. Pat. No. 6,234,165 to Creighton et al., which discloses a baby bottle warmer for use in heating baby bottles. Unfortunately an exothermic reaction based warmer has not been developed in a suitable form for adequately heating baby food pouches. It would be useful to provide a baby food pouch warmer for time starved parents that need a solution to warm a baby food pouch when away home that is portable, easy to use and does not require electricity or batteries. There are currently various types of baby bottle warmers on the market but no solution has been designed to fit the size and shape of a baby food pouch, both pre-made baby food pouches and baby food pouches for home-made baby food as well as being able to heat the baby food pouch without electricity or batteries. The baby food pouch warmer is designed to be light, portable and flexible enabling it to be used with various sizes and shapes of baby food pouches. It can be used in locations that other electrical operated warming devices are not practical such as in parks or at grocery stores for example. Thus the re-usable baby food pouch warmer described herein is designed to create a convenient system for warming, baby food providing an alternative to conventional means of heating in situations where such means may not be available. During use, the metal disc inside the gel warmer is manipulated or clicked to create an exothermic reaction with the sodium acetate thus creating a heating effect. The heat is then transferred through the plastic membrane of the gel warmer to the object it is wrapped around. Specifically, the intended use of this invention is to wrap the gel warmer around plastic baby food pouches or bags containing liquid foods such as baby food, so as to transfer heat from the gel pouch to the food pouch or bag. An important aspect of this invention therefore, lies in providing a warming system specifically to heat liquid foods through the use of a metal disc manipulated in an environment of sodium acetate to create an exothermic reaction. The disadvantage with prior art is that there is no adequate opening in the design of the exothermic gel warmer to allow for a food pouch spout to be accessed from the side or the top of the warmer whilst the food pouch is inside the warmer. Therefore, an important aspect of this invention are the side and top openings allowing for the food pouch spout to be exposed outside of the baby food pouch warmer when the baby food pouch is position inside the baby food pouch warmer. Briefly the pouch consists of two flexible sidewalls sealed to one another on all sides creating a chamber to hold and store liquid including sodium acetate as well as a metal disc. When in use the gel pouch is folded or wrapped around the contents that are intended to be warmed with one external wall of the gel pouch in direct contact with the food pouch or bag that is to be warmed. The gel pouch may then be secured into position around the food pouch or bag through the use of fasteners that are sealed into place along the vertical end walls of the gel warmer. Once the external walls of the gel warmer are in direct contact with the food pouch or bag the metal disc inside the gel pouch may be manipulated or clicked to create an exothermic reaction, creating heat that is transferred to the food pouch or bag through direct contact with the gel warmer. Other features, advantages and objects will become apparent from the specifications and drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 Is a front view of an example of the baby food pouch warmer. FIG. 2 Is a front view of the baby food pouch warmer in an open position with a baby food pouch. FIG. 3 Is a front view of the baby food pouch warmer in an closed position with a baby food pouch. FIG. 4 Is a side view of the baby food pouch warmer. FIG. 5 Is a cross sectional view of the baby food pouch warmer in a closed position with a baby food pouch. DETAILED DESCRIPTION In FIG 1 a baby food pouch warmer 1 is illustrated. The warmer 1 is made of a flexible plastic and/or durable material. The main body of the pouch 1 consists of two flexible sheets 2, 3 which are fused together at the edges 4 forming an airtight and waterproof seal. The fusing of the two flexible sheets forms a pouch 1 in which sodium acetate 9 is stored. A metal disc 5 used to activate a chemical reaction to trigger the heating effect is placed within the pouch directly surrounded by the sodium acetate 9. FIG. 2 depicts the baby food pouch warmer 1 in an open position with a baby food pouch placed in an appropriate position, ready for the baby food pouch warmer 1 to be wrapped around it in a closed position. The baby food pouch warmer 1 is designed to house baby food pouches 6 of different designs including a baby food pouch 6 with a spout on a vertical facing end or a pouch with a spout on a horizontal facing end as shown in FIG.2, or a baby food pouch 6 with a different opening such as a zip lock seal or fully sealed pouch or partially sealed pouch as well as other designs of baby food pouches. FIG. 3 depicts the baby food pouch warmer 1 in a closed position, whereby the baby food pouch warmer 1 is wrapped around the baby food pouch 6 creating a sandwich effect upon whereby the vertical walls of the baby food pouch 6 are in direct contact with the walls of the baby food pouch warmer 1. This positioning allows for heat transference to occur between the baby food pouch 6 and the baby food pouch warmer 1 in order to heat the baby food 10. It is intended that the baby food pouch warmer 1 will take this closed position when warming the baby food pouch 6. FIG. 4 depicts the side view of the baby food pouch warmer 1 consisting of two flexible sheets 2, 3 which are fused together at the edges 4. It is envisioned that press studs 7, or other snap locking or sealing devices may be located along the sealed edge on both vertical ends of the baby food pouch warmer 1. When the baby food pouch warmer 1 is folded and the opposite ends meet the press studs 7 or other sealing device may be closed together forming a seal that holds the baby food pouch warmer 1 in place around the baby food pouch 6. Although preferred embodiments of the invention have been described in detail and illustrated in the drawings it is to be understood that the invention is not limited to these precise embodiments and various changes and modifications may be effected therein without departing from the scope of the present invention.